This is an unofficial reference manual for
LaTeX. See below for the Table of Contents.
If you want a tutorial then please instead visit learnlatex.org
or
see this long list.
This manual has two versions. One has separate web pages for each section or subsection. It's also available as a single web page and as a pdf. Translations to French and Spanish are available at https://ctan.org/pkg/latex2e-help-texinfo; they're maintained separately.
This document is not official. It has not been reviewed by the LaTeX maintainers. Our ultimate goal is to cover all (non-private) LaTeX commands. Your comments and contributions, including bug reports, are very welcome. See our project page for more, including license information and information on how you can contribute to this manual as well as mirror it.
This document is an unofficial reference manual (version of May 2024) for LaTeX2e, a document preparation system.
fontenc
package
\DeclareFontEncoding
\DeclareTextAccent
\DeclareTextAccentDefault
\DeclareTextCommand
& \ProvideTextCommand
\DeclareTextCommandDefault
& \ProvideTextCommandDefault
\DeclareTextComposite
\DeclareTextCompositeCommand
\DeclareTextSymbol
\DeclareTextSymbolDefault
\LastDeclaredEncoding
\UseTextSymbol
& \UseTextAccent
abstract
array
center
description
displaymath
document
enumerate
eqnarray
equation
figure
filecontents
flushleft
flushright
itemize
letter
environment: writing letterslist
math
minipage
picture
quotation
& quote
tabbing
table
tabular
thebibliography
theorem
titlepage
verbatim
verse
\newcommand
& \renewcommand
\providecommand
\makeatletter
& \makeatother
\@ifstar
\newcounter
: Allocating a counter\newlength
\newsavebox
\newenvironment
& \renewenvironment
\newtheorem
\newfont
\protect
\ignorespaces & \ignorespacesafterend
xspace
package\AtBeginDvi
& \AtEndDvi
\AtEndOfClass
& \AtEndOfPackage
\CheckCommand
\ClassError
and \PackageError
and others\CurrentOption
\DeclareOption
\DeclareRobustCommand
\ExecuteOptions
\IfFileExists
& \InputIfFileExists
\LoadClass
& \LoadClassWithOptions
\NeedsTeXFormat
\OptionNotUsed
\PassOptionsToClass
& \PassOptionsToPackage
\ProcessOptions
\ProvidesClass
& \ProvidesPackage
\ProvidesFile
\RequirePackage
& \RequirePackageWithOptions
\enspace
& \quad
& \qquad
\hspace
\hfill
\hss
\spacefactor
\
~
, \nobreakspace
\thinspace
& \negthinspace
\/
\hrulefill
& \dotfill
\bigskip
& \medskip
& \smallskip
\bigbreak
& \medbreak
& \smallbreak
\strut
\vspace
\vfill
\addvspace
This is an unofficial reference manual for the LaTeX2e document preparation system, which is a macro package for the TeX typesetting program (see Overview of LaTeX).
This document’s home page is https://latexref.xyz; it has separate web pages for each topic. Alternatively. https://latexref.xyz/dev/latex2e.html has the entire document on a single page. For other output formats, the sources, and plenty more information, see https://latexref.xyz/dev/.
In this document, we will mostly just use ‘LaTeX’ rather than ‘LaTeX2e’, since the previous version of LaTeX (2.09) was frozen decades ago.
LaTeX is maintained by a group of volunteers (https://latex-project.org). The official documentation written by the LaTeX project is available from their web site. The present document is completely unofficial and has not been written or reviewed by the LaTeX maintainers. Do not send bug reports or anything else about this document to them. Instead, please send all comments to [email protected]. This is a public list; you can (un)subscribe, view the archives, etc., at https://lists.tug.org/latexrefman.
This document is a reference, not a tutorial. There is a vast array of other information available about LaTeX, at all levels. Here are a few introductions.
Two pages of recommended references to LaTeX documentation.
Writing your first document, with a bit of both text and math.
A longer introduction to LaTeX, translated to many languages.
Overview of getting started with TeX and LaTeX.
LaTeX is a system for typesetting documents. It was originally created by Leslie Lamport in 1984, but has been maintained by a group of volunteers for many years now (https://latex-project.org). It is widely used, particularly but not exclusively for mathematical and technical documents.
A LaTeX user writes an input file containing text to be typeset along with interspersed commands. The default encoding for the text is UTF-8 (as of 2018). The commands specify, for example, how the text should be formatted.
LaTeX is implemented as a set of so-called “macros” (a TeX format) which use Donald E. Knuth’s TeX typesetting program or one of its derivatives, collectively known as “engines”. Thus, the user produces output, typically PDF, by giving the input file to a TeX engine. The following sections describe all this in more detail.
The term LaTeX is also sometimes used to mean the language in which the input document is marked up, that is, to mean the set of commands available to a LaTeX user.
The name LaTeX is short for “Lamport TeX”. It is pronounced
LAH-teck or LAY-teck, or sometimes LAY-tecks. Inside a document,
produce the logo with \LaTeX
. Where use of the logo is not
sensible, such as in plain text, write it as ‘LaTeX’.
\DocumentMetadata
: Producing tagged PDF outputLaTeX files have a simple global structure, with a standard beginning and ending. Here is a small example:
\documentclass{article} \begin{document} Hello, \LaTeX\ world. \end{document}
Every LaTeX document has a \begin{document}
line and an
\end{document}
line.
Here, the ‘article’ is the document class. It is implemented in a file article.cls. You can use any document class available on your system. A few document classes are defined by LaTeX itself, and a vast array of others are available. See Document classes.
You can include other LaTeX commands between the
\documentclass
and the \begin{document}
commands.
This area is called the preamble.
The \begin{document}
… \end{document}
pair
defines an environment; the ‘document’ environment (and no
others) is required in all LaTeX documents (see document
).
LaTeX provides many environments that are documented here
(see Environments). Many more are available to you from external
packages, most importantly those available at CTAN (see CTAN: The Comprehensive TeX Archive Network).
The following sections discuss how to produce PDF or other output from a LaTeX input file.
LaTeX produces a main output file and at least two auxiliary files. The main output file’s name ends in either .dvi or .pdf.
.dvi
¶If LaTeX is invoked with the system command latex
then it
produces a DeVice Independent file, with extension .dvi. You
can view this file with a command such as xdvi
, or convert
it to a PostScript .ps
file with dvips
or to a
Portable Document Format .pdf
file with dvipdfmx
.
The contents of the file can be dumped in human-readable form with
dvitype
. A vast array of other DVI utility programs are
available (https://mirror.ctan.org/dviware).
.pdf
¶If LaTeX is invoked via the system command pdflatex
,
among other commands (see TeX engines), then the main output is
a Portable Document Format (PDF) file. Typically this is a
self-contained file, with all fonts and images included.
LaTeX always produces at least two additional files.
.log
¶This transcript file contains summary information such as a list of loaded packages. It also includes diagnostic messages and perhaps additional information for any errors.
.aux
¶Auxiliary information is used by LaTeX for things such as
cross references. For example, the first time that LaTeX finds a
forward reference—a cross reference to something that has not yet
appeared in the source—it will appear in the output as a doubled
question mark ??
. When the referred-to spot does eventually
appear in the source then LaTeX writes its location information to
this .aux
file. On the next invocation, LaTeX reads the
location information from this file and uses it to resolve the
reference, replacing the double question mark with the remembered
location.
LaTeX may produce yet more files, characterized by the filename
ending. These include a .lof
file that is used to make a list of
figures, a .lot
file used to make a list of tables, and a
.toc
file used to make a table of contents (see Table of contents, list of figures, list of tables). A particular class may create others; the list is
open-ended.
LaTeX is a large set of commands (macros) that is executed by a
TeX program (see Overview of LaTeX). Such a set of commands is called a
format, and is embodied in a binary .fmt
file, which can
be read much more quickly than the corresponding TeX source.
This section gives a terse overview of the TeX programs that are commonly available (see also Command line interface).
latex
¶pdflatex
¶In TeX Live (https://tug.org/texlive), if LaTeX is invoked
via either the system command latex
or pdflatex
,
then the pdfTeX engine is run (https://ctan.org/pkg/pdftex).
When invoked as latex
, the main output is a .dvi
file; as pdflatex
, the main output is a .pdf file.
pdfTeX incorporates the e-TeX extensions to Knuth’s original
program (https://ctan.org/pkg/etex), including additional
programming features and bi-directional typesetting, and has plenty of
extensions of its own. e-TeX is available on its own as the system
command etex
, but this is plain TeX (and produces
.dvi).
In other TeX distributions, latex
may invoke e-TeX
rather than pdfTeX. In any case, the e-TeX extensions can be
assumed to be available in LaTeX, and a few extensions beyond
e-TeX, particularly for file manipulation.
lualatex
¶If LaTeX is invoked via the system command lualatex
, the
LuaTeX engine is run (https://ctan.org/pkg/luatex). This
program allows code written in the scripting language Lua
(http://luatex.org) to interact with TeX’s typesetting.
LuaTeX handles UTF-8 Unicode input natively, can handle OpenType
and TrueType fonts, and produces a .pdf file by default.
There is also dvilualatex
to produce a .dvi file.
xelatex
¶If LaTeX is invoked with the system command xelatex
, the
XeTeX engine is run (https://tug.org/xetex). Like LuaTeX,
XeTeX natively supports UTF-8 Unicode and TrueType and OpenType
fonts, though the implementation is completely different, mainly using
external libraries instead of internal code. XeTeX produces a
.pdf file as output; it does not support DVI output.
Internally, XeTeX creates an .xdv
file, a variant of DVI,
and translates that to PDF using the (x
)dvipdfmx
program, but this process is automatic. The .xdv
file is only
useful for debugging.
hilatex
¶If LaTeX is invoked via the system command hilatex
, the
HiTeX engine is run (https://ctan.org/pkg/hitex). This
program produces its own format, named HINT, designed especially for
high-quality typesetting on mobile devices.
platex
¶uplatex
¶These commands provide significant additional support for Japanese and
other languages; the u
variant supports Unicode. See
https://ctan.org/pkg/ptex and https://ctan.org/pkg/uptex.
As of 2019, there is a companion -dev
command and format for
all of the above, except hitex
:
dvilualatex-dev
¶latex-dev
¶lualatex-dev
¶pdflatex-dev
¶platex-dev
¶uplatex-dev
¶xelatex-dev
¶These are candidates for an upcoming LaTeX release. The main purpose is to find and address compatibility problems before an official release.
These -dev
formats make it easy for anyone to help test
documents and code: you can run, say, pdflatex-dev
instead of
pdflatex
, without changing anything else in your environment.
Indeed, it is easiest and most helpful to always run the -dev
versions instead of bothering to switch back and forth. During quiet
times after a release, the commands will be equivalent.
These are not daily snapshots or untested development code. They undergo the same extensive regression testing by the LaTeX team before being released.
For more information, see “The LaTeX release workflow and the
LaTeX dev
formats” by Frank Mittelbach, TUGboat 40:2,
https://tug.org/TUGboat/tb40-2/tb125mitt-dev.pdf.
To a first approximation, most input characters in LaTeX print as themselves. But there are exceptions, as discussed in the following sections.
The input to TeX (or any computer program) ultimately consists of a sequence of bytes. (Nowadays, a byte is almost universally an eight-bit number, i.e., an integer between 0 and 255, inclusive.) The input encoding defines how to interpret that sequence of bytes, and thus how LaTeX behaves.
Today, by far the most common way to encode text is with UTF-8, a so-called “Unicode Transformation Format” which specifies how to transform a sequence of 8-bit bytes to Unicode code points, which are defined independent of any particular representation. The Unicode encoding defines code points for virtually all characters used today in written text.
When TeX was created, Unicode and UTF-8 did not exist and the 7-bit ASCII encoding was by far the most widely used. So TeX does not require Unicode for text input. UTF-8 is a superset of ASCII, so a pure 7-bit ASCII document is also UTF-8.
Since 2018, the default input encoding for LaTeX is UTF-8.
Some methods for handling documents written in some other encoding,
such as ISO-8859-1 (Latin 1), are explained in inputenc
package.
You can easily find more about all these topics in any introductory computer text or online. For example, you might start at: https://en.wikipedia.org/wiki/Unicode.
A ligature combines two or more letters (more generally, characters) into a single glyph. For example, in Latin-based typography, the two letters ‘f’ and ‘i’ are often combined into the glyph ‘fi’.
TeX supports ligatures automatically. To continue the example, if the input has the word ‘fine’, written as four separate ASCII characters, TeX will output the word ‘fine’ (with the default fonts), with three typeset glyphs.
In traditional TeX, the available ligatures, if any, are defined by the current font. TeX also uses the ligature mechanism to produce a few typographical characters which were not available in any computer encoding when TeX was invented. In all, in the original Computer Modern fonts, the following input character sequences are defined to lead to ligatures:
ff (ff ligature, U+FB00)
fi (fi ligature, U+FB01)
fl (fl ligature, U+FB02)
ffi (ffi ligature, U+FB03)
ffl (ffl ligature, U+FB04)
“ (left double quotation mark, U+201C)
” (right double quotation mark, U+201D)
– (en-dash, U+2013)
— (em-dash, U+2014)
!‘ (inverted exclamation mark, U+00A1)
?‘ (inverted question mark, U+00BF)
(For the f-ligatures above, the text in parentheses shows the individual characters, so in the typeset output you can easily see the difference between the ligature and the original character sequence.)
Nowadays it’s usually possible to directly input the punctuation characters as Unicode characters, and LaTeX supports that (see previous section). But even today, it can still often be useful to use the ASCII ligature input form; for example, the difference between an en-dash and em-dash, as a single glyph, can be all but impossible to discern, but the difference between two and three ASCII hyphen characters is clear. Similarly with quotation marks, in some fonts.
Thus, even the engines with native support for UTF-8, namely LuaTeX and XeTeX, also support the ASCII ligature input sequences by default, independent of the font used. They also need to do so for compatibility.
By the way, the f-ligatures are also available in Unicode (the “Alphabetic Presentation Forms” block starting at U+FB00), but it’s almost never desirable to use them as input characters, since in principle it should be up to the typesetter and the current font whether to use ligatures. Also, in practice, using them will typically cause searches to fail, that is, a search for the two characters ‘fi’ will not be matched by the ligature ‘fi’ at U+FB01.
\ { } % $ & _ ^ # ~
¶Besides ligatures (see previous section), a few individual characters have special meaning to LaTeX. They are called reserved characters or special characters. Here they are:
Introduces a command name, as seen throughout this manual.
Delimits a required argument to a command or a level of grouping, as seen throughout this manual.
Starts a comment: the ‘%’ and all remaining characters on the current line are ignored.
Starts and ends math mode (see Math formulas).
Separates cells in a table (see tabular
).
Introduce a subscript or superscript, respectively, in math (see Subscripts & superscripts); they produce an error outside math mode. As a little-used special feature, two superscript characters in a row can introduce special notation for an arbitrary character.
Stands for arguments in a macro definition (see \newcommand
& \renewcommand
).
Produces a nonbreakable interword space (see ~
, \nobreakspace
).
See Printing special characters, for how to typeset these characters when you need them literally.
In the LaTeX input file, a command name starts with a backslash
character, \
. The name itself then consists of either
(a) a string of letters or (b) a single non-letter.
LaTeX commands names are case sensitive; for example,
\pagebreak
differs from \Pagebreak
(the latter is not a
standard command). Most command names are lowercase, but in any event
you must enter all commands in the same case as they are defined.
A command may be followed by zero, one, or more arguments. These
arguments may be either required or optional. Required arguments are
contained in curly braces, {...}
. Optional arguments are
contained in square brackets, [...]
. Generally, but not
universally, if the command accepts an optional argument, it comes
first, before any required arguments; optional arguments could come
after required arguments, or both before and after.
Inside of an optional argument, to use the character close square
bracket (]
) hide it inside curly braces, as
in \item[closing bracket {]}]
. Similarly, if an optional
argument comes last, with no required argument after it, then to make
the first character of the following text be an open square bracket,
hide it inside curly braces.
LaTeX has the convention that some commands have a *
form
that is closely related to the form without a *
, such as
\chapter
and \chapter*
. The difference in behavior
varies from command to command.
This manual describes all accepted options and *
-forms for the
commands it covers (barring unintentional omissions, a.k.a. bugs).
As of the 2020-10-01 release of LaTeX, the expl3
and
xparse
packages are part of the LaTeX2e format. They
provide a completely different underlying programming language
syntax. We won’t try to cover that in this document; see the related
package documentation and other LaTeX manuals.
Synopsis:
\begin{environment-name} ... \end{environment-name}
An environment is an area of LaTeX source, inside of which
there is a distinct behavior. For instance, for poetry in LaTeX
put the lines between \begin{verse}
and \end{verse}
.
\begin{verse} There once was a man from Nantucket \\ ... \end{verse}
See Environments, for a list of environments. Particularly notable is
that every LaTeX document must have a document
environment,
a \begin{document} ... \end{document}
pair.
The environment-name at the beginning must exactly match that at
the end. This includes the case where environment-name ends in a
star (*
); both the \begin
and \end
texts must
include the star.
Environments may have arguments, including optional arguments. This example produces a table. The first argument is optional (and causes the table to be aligned on its top row) while the second argument is required (it specifies the formatting of columns).
\begin{tabular}[t]{r|l} ... rows-of-table ... \end{tabular}
\DocumentMetadata
: Producing tagged PDF output ¶The \DocumentMetadata
command was added to LaTeX in 2022.
It enables so-called “tagging” of the PDF output, aiding
accessibility of the PDF. It is supported best with LuaLaTeX;
pdfLaTeX and XeLaTeX are supported as well as possible
(see TeX engines).
It is unlike nearly any other command in LaTeX in that it must
occur before the \documentclass
command that starts a LaTeX
document proper (see \documentclass). Therefore it must be
called with \RequirePackage
rather than \usepackage
(see \RequirePackage).
This support is still in development, so we will not try to list all
the possible settings. Please see the
documentmetadata-support-doc
document, part of the
latex-lab
package (https://ctan.org/pkg/latex-lab). Here
is a simple example which enables most tagging currently implemented:
\DocumentMetadata{testphase={phase-III,firstaid}} \documentclass{article} ...
As you can see from the key name testphase
, this is all still
in an experimental phase. The LaTeX developers strongly encourage
users to give it a try and report problems, so it can be improved.
The Comprehensive TeX Archive Network, CTAN, is the TeX and LaTeX community’s repository of free material. It is a set of Internet sites around the world that offer material related to LaTeX for download. Visit CTAN on the web at https://ctan.org.
This material is organized into packages, discrete bundles that typically offer some coherent functionality and are maintained by one person or a small number of people. For instance, many publishers have a package that allows authors to format papers to that publisher’s specifications.
In addition to its massive holdings, the ctan.org
web site
offers features such as search by name or by functionality.
CTAN is not a single host, but instead is a set of hosts, one of which is the so-called “master”. The master host actively manages the material, for instance, by accepting uploads of new or updated packages. For many years, it has been hosted by the German TeX group, DANTE e.V.
Other sites around the world help out by mirroring, that is, automatically syncing their collections with the master site and then in turn making their copies publicly available. This gives users close to their location better access and relieves the load on the master site. The list of mirrors is at https://ctan.org/mirrors.
The document’s overall class is defined with the \documentclass
command, which is normally the first command in a LaTeX source
file.
\documentclass[options]{class}
The following document class names are built into LaTeX. Many other document classes are available as separate packages (see Overview of LaTeX).
article
For a journal article, a presentation, and miscellaneous general use.
book
Full-length books, including chapters and possibly including front matter, such as a preface, and back matter, such as an appendix (see Front/back matter).
letter
Mail, optionally including mailing labels (see Letters).
report
For documents of length between an article
and a book
,
such as technical reports or theses, which may contain several chapters.
slides
For slide presentations—rarely used nowadays. The
beamer
package is perhaps the most prevalent replacement
(https://ctan.org/pkg/beamer). See beamer
template, for a
small template for a beamer document.
Standard options are described in the next section.
You can specify global options or class options to the
\documentclass
command by enclosing them in square brackets. To
specify more than one option, separate them with a comma.
\documentclass[option1,option2,...]{class}
LaTeX automatically passes options specified for
\documentclass
on to any other loaded classes that can handle
them.
Here is the list of the standard class options.
All of the standard classes except slides
accept the following
options for selecting the typeface size; the default is 10pt
:
10pt 11pt 12pt
All of the standard classes accept these options for selecting the paper size (dimensions are listed height by width):
a4paper
210 by 297mm (about 8.25 by 11.75 inches)
a5paper
148 by 210mm (about 5.8 by 8.3 inches)
b5paper
176 by 250mm (about 6.9 by 9.8 inches)
executivepaper
7.25 by 10.5 inches
legalpaper
8.5 by 14 inches
letterpaper
8.5 by 11 inches (the default)
When using one of the engines pdfLaTeX, LuaLaTeX, or XeLaTeX
(see TeX engines), options other than letterpaper
set
the print area but you must also set the physical paper size. Usually,
the geometry
package is the best way to do that; it
provides flexible ways of setting the print area and physical page size.
Otherwise, setting the paper size is engine-dependent. For example,
with pdfLaTeX, you could include \pdfpagewidth=\paperwidth
and
\pdfpageheight=\paperheight
in the preamble.
Miscellaneous other options:
draft
¶final
Mark (draft
) or do not mark (final
) overfull boxes with a
black box in the margin; default is final
.
fleqn
¶Put displayed formulas flush left; default is centered.
landscape
¶Selects landscape format; default is portrait.
leqno
¶Put equation numbers on the left side of equations; default is the right side.
openbib
¶Use “open” bibliography format.
titlepage
¶notitlepage
Specifies whether there is a separate page for the title information and
for the abstract also, if there is one. The default for the
report
class is titlepage
, for the other classes it is
notitlepage
.
The following options are not available with the slides
class.
onecolumn
twocolumn
Typeset in one or two columns; default is onecolumn
.
oneside
¶twoside
Selects one- or two-sided layout; default is oneside
, except
that in the book
class the default is twoside
.
For one-sided printing, the text is centered on the page. For two-sided
printing, the \evensidemargin
(\oddsidemargin
) parameter
determines the distance on even (odd) numbered pages between the left
side of the page and the text’s left margin, with \oddsidemargin
being 40% of the difference between \paperwidth
and
\textwidth
, and \evensidemargin
is the remainder.
openright
openany
Determines if a chapter should start on a right-hand page; default is
openright
for book
, and openany
for report
.
The slides
class offers the option clock
for printing
the time at the bottom of each note.
\usepackage
: Additional packages ¶To load a package pkg, with the package options given in the comma-separated list options:
\usepackage[options]{pkg}[mindate]
To specify more than one package you can separate them with a comma,
as in \usepackage{pkg1,pkg2,...}
, or use multiple
\usepackage
commands.
If the mindate optional argument is given, LaTeX gives a
warning if the loaded package has an earlier date, i.e., is too old.
The mindate argument must be in the form YYYY/MM/DD
.
More info on this: https://tex.stackexchange.com/questions/47743.
\usepackage
must be used in the document preamble, between the
\documentclass
declaration and the \begin{document}
.
Occasionally it is necessary to load packages before the
\documentclass
; see \RequirePackage
for that
(see \RequirePackage).
Any options given in the global \documentclass
command that are
unknown to the selected document class are passed on to the packages
loaded with \usepackage
.
You can create new document classes and new packages. For instance, if
your memos must satisfy some local requirements, such as a
standard header for each page, then you could create a new class
smcmemo.cls
and begin your documents with
\documentclass{smcmemo}
.
What separates a package from a document class is that the commands in
a package are useful across classes while those in a document class
are specific to that class. Thus, a command to set page headers is
for a package while a command to make the page headers be
Memo from the SMC Math Department
is for a class.
Inside of a class or package definition you can use the at-sign
@
as a character in command names without having to surround
the code containing that command with \makeatletter
and
\makeatother
(see \makeatletter
& \makeatother
). This
allows you to create commands that users will not accidentally
redefine.
It is also highly desirable to prefix class- or package-specific
commands with your package name or similar string, to prevent your
definitions from clashing with those from other packages. For
instance, the class smcmemo
might have commands
\smc@tolist
, \smc@fromlist
, etc.
A class file or package file typically has four parts.
\NeedsTeXFormat
and \ProvidesClass
or \ProvidesPackage
commands.
smcmemo
class might be called with an option to read in a file with a list of
people for the to-head, as \documentclass[mathto]{smcmemo}
, and
therefore needs to define a command
\newcommand{\setto}[1]{\def\@tolist{#1}}
used in that
file.
\documentclass[option list]{class
name}
, to modify the behavior of the class. An example is when you
declare \documentclass[11pt]{article}
to set the default
document font size.
Here is a starting class file, which should be saved as stub.cls where LaTeX can find it, for example in the same directory as the .tex file.
\NeedsTeXFormat{LaTeX2e} \ProvidesClass{stub}[2017/07/06 stub to start building classes from] \DeclareOption*{\PassOptionsToClass{\CurrentOption}{article}} \ProcessOptions\relax \LoadClass{article}
It identifies itself, handles the class options via the default of
passing them all to the article
class, and then loads the
article
class to provide the basis for this class’s code.
For more, see the official guide for class and package writers, the Class Guide, at https://ctan.org/pkg/clsguide (much of the description here derives from this document), or the tutorial at https://tug.org/TUGboat/tb26-3/tb84heff.pdf.
See Class and package commands, for some of the commands specifically intended for class and package writers.
LaTeX comes with powerful font capacities. For one thing, its New Font Selection Scheme allows you to work easily with the font families in your document (for instance, see Font styles). And, LaTeX documents can use most fonts that are available today, including versions of Times Roman, Helvetica, Courier, etc. (Note, though, that many fonts do not have support for mathematics.)
The first typeface in the TeX world was the Computer Modern family, developed by Donald Knuth. It is the default for LaTeX documents and is still the most widely used. But changing to another font often only involves a few commands. For instance, putting the following in your preamble gives you a Palatino-like font, which is handsome and more readable online than many other fonts, while still allowing you to typeset mathematics. (This example is from Michael Sharpe, https://math.ucsd.edu/~msharpe/RcntFnts.pdf.)
\usepackage[osf]{newpxtext} % osf for text, not math \usepackage{cabin} % sans serif \usepackage[varqu,varl]{inconsolata} % sans serif typewriter \usepackage[bigdelims,vvarbb]{newpxmath} % bb from STIX \usepackage[cal=boondoxo]{mathalfa} % mathcal
In addition, the xelatex
or lualatex
engines allow
you to use any fonts on your system that are in OpenType or TrueType
format (see TeX engines).
The LaTeX Font Catalogue (https://tug.org/FontCatalogue) shows font sample graphics and copy-and-pasteable source to use many fonts, including many with support for mathematics. It aims to cover all Latin alphabet free fonts available for easy use with LaTeX.
More information is also available from the TeX Users Group, at https://www.tug.org/fonts/.
fontenc
package ¶Synopsis:
\usepackage[font_encoding]{fontenc}
or
\usepackage[font_encoding1, font_encoding2, ...]{fontenc}
Specify the font encodings. A font encoding is a mapping of the character codes to the font glyphs that are used to typeset your output.
This package only applies if you use the pdflatex
engine
(see TeX engines). If you use the xelatex
or
lualatex
engine then instead use the fontspec
package.
TeX’s original font family, Computer Modern, has a limited character
set. For instance, to make common accented characters you must use
\accent
(see \accent
) but this disables hyphenation. TeX
users have agreed on a number of standards to access the larger sets of
characters provided by modern fonts. If you are using
pdflatex
then put this in the preamble
\usepackage[T1]{fontenc}
gives you support for the most widespread European languages, including French, German, Italian, Polish, and others. In particular, if you have words with accented letters then LaTeX will hyphenate them and your output can be copied and pasted. (The optional second line allows you to directly enter accented characters into your source file.)
If you are using an encoding such as T1
and the characters appear
blurry or do not magnify well then your fonts may be bitmapped,
sometimes called raster or Type 3. You want vector fonts. Use a
package such as lmodern
or cm-super
to get a font that
extends LaTeX’s default using vector fonts.
For each font_encoding given as an option but not already
declared, this package loads the encoding definition files, named
font_encodingenc.def. It also sets \encodingdefault
to be the last encoding in the option list.
These are the common values for font_encoding:
OT1
¶The original 7-bit encoding for TeX. Limited to mostly English characters.
OMS, OML
Math symbols and math letters encoding.
T1
¶TeX text extended. Sometimes called the Cork encoding for the users group meeting where it was developed (1990). Gives access to most European accented characters. The most common option for this package.
TS1
¶Text Companion encoding.
LaTeX’s default is to load OML
, T1
, OT1
, and
then OMS
, and set the default to OT1
.
Even if you do not use accented letters, you may need to specify a font encoding if your font requires it.
If you use T1
encoded fonts other than the default Computer
Modern family then you may need to load the package that selects your
fonts before loading fontenc, to prevent the system from loading
any T1
encoded fonts from the default.
The LaTeX team reserves encoding names starting with: ‘T’ for the standard text encodings with 256 characters, ‘TS’ for symbols that extend the corresponding T encodings, ‘X’ for test encodings, ‘M’ for standard math encodings with 256 characters, ‘A’ for special applications, ‘OT’ for standard text encodings with 128 characters, and ‘OM’ for standard math encodings with 128 characters (‘O’ stands for ‘obsolete’).
This package provides a number of commands, detailed below. Many of them are encoding-specific, so if you have defined a command that works for one encoding but the current encoding is different then the command is not in effect.
\DeclareFontEncoding
\DeclareTextAccent
\DeclareTextAccentDefault
\DeclareTextCommand
& \ProvideTextCommand
\DeclareTextCommandDefault
& \ProvideTextCommandDefault
\DeclareTextComposite
\DeclareTextCompositeCommand
\DeclareTextSymbol
\DeclareTextSymbolDefault
\LastDeclaredEncoding
\UseTextSymbol
& \UseTextAccent
\DeclareFontEncoding
¶Synopsis:
\DeclareFontEncoding{encoding}{text-settings}{math-settings}
Declare the font encoding encoding. It also saves the value of
encoding in \LastDeclaredEncoding
(see \LastDeclaredEncoding
).
The file t1enc.def contains this line (followed by many others).
\DeclareFontEncoding{T1}{}{}
The text-settings are the commands that LaTeX will run every
time it switches from one encoding to another with the
\selectfont
and \fontencoding
commands. The
math-settings are the commands that LaTeX will use whenever the
font is accessed as a math alphabet.
LaTeX ignores any space characters inside text-settings and math-settings, to prevent unintended spaces in the output.
If you invent an encoding you should pick a two or three letter name starting with ‘L’ for ‘local’, or ‘E’ for ‘experimental’.
Note that output encoding files may be read several times by LaTeX so
using, e.g., \newcommand
may cause an error. In addition, such
files should contain \ProvidesFile
line (see Class and package commands).
Note also that you should use the \...Default
commands only in a
package, not in the encoding definition files, since those files
should only contain declarations specific to that encoding.
\DeclareTextAccent
¶Synopsis:
\DeclareTextAccent{cmd}{encoding}{slot}
Define an accent, to be put on top of other glyphs, in the encoding encoding at the location slot.
A slot is the number identifying a glyph within a font.
This line from t1enc.def declares that to make a circumflex
accent as in \^A
, the system will put the accent in slot 2
over the ‘A’ character, which is represented in ASCII as 65.
(This holds unless there is a relevant DeclareTextComposite
or
\DeclareTextCompositeCommand
declaration;
see \DeclareTextComposite
.)
\DeclareTextAccent{\^}{T1}{2}
If cmd has already been defined then \DeclareTextAccent
does not give an error but it does log the redefinition in the
transcript file.
\DeclareTextAccentDefault
¶Synopsis:
\DeclareTextAccentDefault{\cmd}{encoding}
If there is an encoding-specific accent command \cmd but there is
no associated \DeclareTextAccent
for that encoding then this
command will pick up the slack, by saying to use it as described for
encoding.
For example, to make the encoding OT1
be the default encoding for
the accent \"
, declare this.
\DeclareTextAccentDefault{\"}{OT1}
If you issue a \"
when the current encoding does not have a
definition for that accent then LaTeX will use the definition from
OT1
That is, this command is equivalent to this call (see \UseTextSymbol
& \UseTextAccent
).
\DeclareTextCommandDefault[1]{\cmd} {\UseTextAccent{encoding}{\cmd}{#1}}
Note that \DeclareTextAccentDefault
works for any one-argument
fontenc command, not just the accent command.
\DeclareTextCommand
& \ProvideTextCommand
¶Synopsis, one of:
\DeclareTextCommand{\cmd}{encoding}{defn} \DeclareTextCommand{\cmd}{encoding}[nargs]{defn} \DeclareTextCommand{\cmd}{encoding}[nargs][optargdefault]{defn}
or one of:
\ProvideTextCommand{\cmd}{encoding}{defn} \ProvideTextCommand{\cmd}{encoding}[nargs]{defn} \ProvideTextCommand{\cmd}{encoding}[nargs][optargdefault]{defn}
Define the command \cmd
, which will be specific to one
encoding. The command name cmd must be preceded by a backslash,
\
. These commands can only appear in the preamble. Redefining
\cmd does not cause an error. The defined command will be robust
even if the code in defn is fragile (see \protect
).
For example, the file t1enc.def contains this line.
\DeclareTextCommand{\textperthousand}{T1}{\%\char 24 }
With that, you can express parts per thousand.
\usepackage[T1]{fontenc} % in preamble ... Legal limit is \( 0.8 \)\textperthousand.
If you change the font encoding to OT1
then you get an error like
‘LaTeX Error: Command \textperthousand unavailable in encoding
OT1’.
The \ProvideTextCommand
variant does the same, except that it
does nothing if \cmd
is already defined. The
\DeclareTextSymbol
command is faster than this one for simple
slot-to-glyph association (see \DeclareTextSymbol
)
The optional nargs and optargdefault arguments play the same
role here as in \newcommand
(see \newcommand
& \renewcommand
). Briefly, nargs is an integer from 0 to 9
specifying the number of arguments that the defined command
\cmd
takes. This number includes any optional argument.
Omitting this argument is the same as specifying 0, meaning that
\cmd
will have no arguments. And, if optargdefault
is present then the first argument of \cmd
is optional,
with default value optargdefault (which may be the empty string).
If optargdefault is not present then \cmd
does not
take an optional argument.
\DeclareTextCommandDefault
& \ProvideTextCommandDefault
¶Synopsis:
\DeclareTextCommandDefault{\cmd}{defn}
or:
\ProvideTextCommandDefault{\cmd}{defn}
Give a default definition for \cmd
, for when that command
is not defined in the encoding currently in force. This default should
only use encodings known to be available.
This makes \copyright
available.
\DeclareTextCommandDefault{\copyright}{\textcircled{c}}
It uses only an encoding (OMS) that is always available.
The \DeclareTextCommandDefault
should not occur in the encoding
definition files since those files should declare only commands for use
when you select that encoding. It should instead be in a package.
As with the related non-default commands, the
\ProvideTextCommandDefault
has exactly the same behavior as
\DeclareTextCommandDefault
except that it does nothing if
\cmd
is already defined (see \DeclareTextCommand
& \ProvideTextCommand
). So, packages can use it to provide fallbacks
that other packages can improve upon.
\DeclareTextComposite
¶Synopsis:
\DeclareTextComposite{\cmd}{encoding}{simple_object}{slot}
Access an accented glyph directly, that is, without having to put an accent over a separate character.
This line from t1enc.def means that \^o
will cause
LaTeX to typeset lowercase ‘o’ by taking the character
directly from slot 224 in the font.
\DeclareTextComposite{\^}{T1}{o}{244}
See fontenc
package, for a list of common encodings. The
simple_object should be a single character or a single command.
The slot argument is usually a positive integer represented in
decimal (although octal or hexadecimal are possible). Normally
\cmd has already been declared for this encoding, either with
\DeclareTextAccent
or with a one-argument
\DeclareTextCommand
. In t1enc.def, the above line follows
the \DeclareTextAccent{\^}{T1}{2}
command.
\DeclareTextCompositeCommand
¶Synopsis:
\DeclareTextCompositeCommand{\cmd}{encoding}{arg}{code}
A more general version of \DeclareTextComposite
that runs
arbitrary code with \cmd
.
This allows accents on ‘i’ to act like accents on dotless i,
\i
.
\DeclareTextCompositeCommand{\'}{OT1}{i}{\'\i}
See fontenc
package, for a list of common encodings. Normally
\cmd
will have already been declared with \DeclareTextAccent
or as a one argument \DeclareTextCommand
.
\DeclareTextSymbol
¶Synopsis:
\DeclareTextSymbol{\cmd}{encoding}{slot}
Define a symbol in the encoding encoding at the location slot. Symbols defined in this way are for use in text, not mathematics.
For example, this line from t1enc.def declares the number of the glyph to use for «, the left guillemet.
\DeclareTextSymbol{\guillemetleft}{T1}{19}
The command \DeclareTextCommand{\guillemetleft}{T1}{\char
19}
has the same effect but is slower (see \DeclareTextCommand
& \ProvideTextCommand
).
See fontenc
package, for a list of common encodings. The slot
can be specified in decimal, or octal (as in '023
), or
hexadecimal (as in "13
), although decimal has the advantage that
single quote or double quote could be redefined by another package.
If \cmd
has already been defined then
\DeclareTextSymbol
does not give an error but it does log the
redefinition in the transcript file.
\DeclareTextSymbolDefault
¶Synopsis:
\DeclareTextSymbolDefault{\cmd}{encoding}
If there is an encoding-specific symbol command \cmd
but
there is no associated \DeclareTextSymbol
for that encoding, then
this command will pick up the slack, by saying to get the symbol as
described for encoding.
For example, to declare that if the current encoding has no meaning for
\textdollar
then use the one from OT1
, declare this.
\DeclareTextSymbolDefault{\textdollar}{OT1}
That is, this command is equivalent to this call (see \UseTextSymbol
& \UseTextAccent
).
\DeclareTextCommandDefault{\cmd} {\UseTextSymbol{encoding}{\cmd}}
Note that \DeclareTextSymbolDefault
can be used to define a
default for any zero-argument fontenc command.
\LastDeclaredEncoding
¶Synopsis:
\LastDeclaredEncoding
Get the name of the most recently declared encoding. The
\DeclareFontEncoding
command stores the name so that it can be
retrieved with this command (see \DeclareFontEncoding
).
This relies on \LastDeclaredEncoding
rather than give the
name of the encoding explicitly.
\DeclareFontEncoding{JH1}{}{} \DeclareTextAccent{\'}{\LastDeclaredEncoding}{0}
\UseTextSymbol
& \UseTextAccent
¶Synopsis:
\UseTextSymbol{encoding}{\cmd}
or:
\UseTextAccent{encoding}{\cmd}{text}
Use a symbol or accent not from the current encoding.
In general, to use a fontenc command in an encoding where it is not defined, and if the command has no arguments, then you can use it like this:
\UseTextSymbol{OT1}{\ss}
which is equivalent to this (note the outer braces form a group, so LaTeX
reverts back to the prior encoding after the \ss
):
{\fontencoding{OT1}\selectfont\ss}
Similarly, to use a fontenc command in an encoding where it is not defined, and if the command has one argument, you can use it like this:
\UseTextAccent{OT1}{\'}{a}
which is equivalent to this (again note the outer braces forming a group):
{fontencoding{OT1}\selectfont\'{\fontencoding{enc_in_use}\selectfont a}}
Here, enc_in_use is the encoding in force before this sequence
of commands, so that ‘a’ is typeset using the current encoding
and only the accent is taken from OT1
.
The following type style commands are supported by LaTeX.
In the table below the listed commands, the \text...
commands,
are used with an argument as in \textit{text}
. This is
the preferred form. But shown after it in parenthesis is the
corresponding declaration form, which is often useful. This
form takes no arguments, as in {\itshape text}
. The
scope of the declaration form lasts until the next type style command
or the end of the current group. In addition, each has an environment
form such as \begin{itshape}...\end{itshape}
, which we’ll
describe further at the end of the section.
These commands, in any of the three forms, are cumulative; for instance
you can get bold sans serif by saying either of
\sffamily\bfseries
or \bfseries\sffamily
.
One advantage of these commands is that they automatically insert italic
corrections if needed (see \/
). Specifically, they insert the
italic correction unless the following character is in the list
\nocorrlist
, which by default consists of period and comma.
To suppress the automatic insertion of italic correction, use
\nocorr
at the start or end of the command argument, such as
\textit{\nocorr text}
or \textsc{text \nocorr}
.
\textrm (\rmfamily)
¶Roman.
\textit (\itshape)
¶Italics.
\textmd (\mdseries)
¶Medium weight (default).
\textbf (\bfseries)
¶Boldface.
\textup (\upshape)
¶Upright (default).
\textsl (\slshape)
¶Slanted.
\textsf (\sffamily)
¶Sans serif.
\textsc (\scshape)
¶Small caps.
\texttt (\ttfamily)
¶Typewriter.
\textnormal (\normalfont)
¶Main document font.
Although it also changes fonts, the \emph{text}
command
is semantic, for text to be emphasized, and should not be used as a
substitute for \textit
. For example, \emph{start
text \emph{middle text} end text}
will result in the
start text and end text in italics, but middle text
will be in roman.
LaTeX also provides the following commands, which unconditionally
switch to the given style, that is, are not cumulative. They are
used as declarations: {\cmd...}
instead of
\cmd{...}
.
(The unconditional commands below are an older version of font switching. The earlier commands are an improvement in most circumstances. But sometimes an unconditional font switch is what is needed.)
\bf
¶Switch to bold face.
\cal
¶Switch to calligraphic letters for math.
\it
¶Italics.
\rm
¶Roman.
\sc
¶Small caps.
\sf
¶Sans serif.
\sl
¶Slanted (oblique).
\tt
¶Typewriter (monospace, fixed-width).
The \em
command is the unconditional version of \emph
.
The following commands are for use in math mode. They are not
cumulative, so \mathbf{\mathit{symbol}}
does not
create a boldface and italic symbol; instead, it will just be in
italics. This is because typically math symbols need consistent
typographic treatment, regardless of the surrounding environment.
\mathrm
¶Roman, for use in math mode.
\mathbf
¶Boldface, for use in math mode.
\mathsf
¶Sans serif, for use in math mode.
\mathtt
¶Typewriter, for use in math mode.
\mathit
(\mit)
Italics, for use in math mode.
\mathnormal
¶For use in math mode, e.g., inside another type style declaration.
\mathcal
¶Calligraphic letters, for use in math mode.
In addition, the command \mathversion{bold}
can be used for
switching to bold letters and symbols in
formulas. \mathversion{normal}
restores the default.
Finally, the command \oldstylenums{numerals}
will
typeset so-called “old-style” numerals, which have differing heights
and depths (and sometimes widths) from the standard “lining”
numerals, which all have the same height as uppercase letters.
LaTeX’s default fonts support this, and will respect \textbf
(but not other styles; there are no italic old-style numerals in
Computer Modern). Many other fonts have old-style numerals also;
sometimes package options are provided to make them the default. FAQ
entry: https://www.texfaq.org/FAQ-osf.
The following standard type size commands are supported by LaTeX. The table shows the command name and the corresponding actual font size used (in points) with the ‘10pt’, ‘11pt’, and ‘12pt’ document size options, respectively (see Document class options).
Command | 10pt | 11pt | 12pt |
---|---|---|---|
\tiny | 5 | 6 | 6 |
\scriptsize | 7 | 8 | 8 |
\footnotesize | 8 | 9 | 10 |
\small | 9 | 10 | 10.95 |
\normalsize (default) | 10 | 10.95 | 12 |
\large | 12 | 12 | 14.4 |
\Large | 14.4 | 14.4 | 17.28 |
\LARGE | 17.28 | 17.28 | 20.74 |
\huge | 20.74 | 20.74 | 24.88 |
\Huge | 24.88 | 24.88 | 24.88 |
The commands are listed here in declaration (not environment) form, since that is how they are typically used. For example.
\begin{quotation} \small The Tao that can be named is not the eternal Tao. \end{quotation}
Here, the scope of the \small
lasts until the end of the
quotation
environment. It would also end at the next type
style command or the end of the current group, so you could enclose it
in curly braces {\small This text is typeset in the small font.}
.
Trying to use these commands in math, as with $\small mv^2/2$
,
results in ‘LaTeX Font Warning: Command \small
invalid in math mode’, and the font size doesn’t
change. To work with a too-large formula, often the best option is to
use the displaymath
environment (see Math formulas), or
one of the environments from the amsmath
package. For inline
mathematics, such as in a table of formulas, an alternative is something
like {\small $mv^2/2$}
. (Sometimes \scriptsize
and
\scriptstyle
are confused. Both change the font size, but the
latter also changes a number of other aspects of how mathematics is
typeset. See Math styles.)
An environment form of each of these commands is also defined; for
instance, \begin{tiny}...\end{tiny}
. However, in practice
this form can easily lead to unwanted spaces at the beginning and/or
end of the environment without careful consideration, so it’s
generally less error-prone to stick to the declaration form.
(Aside: Technically, due to the way LaTeX defines \begin
and
\end
, nearly every command that does not take an argument
technically has an environment form. But in almost all cases, it would
only cause confusion to use it. The reason for mentioning the
environment form of the font size declarations specifically is that
this particular use is not rare.)
These commands are primarily intended for writers of macros and packages. The commands listed here are only a subset of the available ones.
\fontencoding{encoding}
¶Select the font encoding, the encoding of the output font. There are a
large number of valid encodings. The most common are OT1
,
Knuth’s original encoding for Computer Modern (the default), and
T1
, also known as the Cork encoding, which has support for the
accented characters used by the most widespread European languages
(German, French, Italian, Polish and others), which allows TeX to
hyphenate words containing accented letters. For more, see
https://ctan.org/pkg/encguide.
\fontfamily{family}
¶Select the font family. The web page https://tug.org/FontCatalogue/ provides one way to browse through many of the fonts easily used with LaTeX. Here are examples of some common families.
pag | Avant Garde |
fvs | Bitstream Vera Sans |
pbk | Bookman |
bch | Charter |
ccr | Computer Concrete |
cmr | Computer Modern |
cmss | Computer Modern Sans Serif |
cmtt | Computer Modern Typewriter |
pcr | Courier |
phv | Helvetica |
fi4 | Inconsolata |
lmr | Latin Modern |
lmss | Latin Modern Sans |
lmtt | Latin Modern Typewriter |
pnc | New Century Schoolbook |
ppl | Palatino |
ptm | Times |
uncl | Uncial |
put | Utopia |
pzc | Zapf Chancery |
\fontseries{series}
¶Select the font series. A series combines a weight and a width. Typically, a font supports only a few of the possible combinations. Some common combined series values include:
m | Medium (normal) |
b | Bold |
c | Condensed |
bc | Bold condensed |
bx | Bold extended |
The possible values for weight, individually, are:
ul | Ultra light |
el | Extra light |
l | Light |
sl | Semi light |
m | Medium (normal) |
sb | Semi bold |
b | Bold |
eb | Extra bold |
ub | Ultra bold |
The possible values for width, individually, are (the meaning and relationship of these terms varies with individual typefaces):
uc | Ultra condensed |
ec | Extra condensed |
c | Condensed |
sc | Semi condensed |
m | Medium |
sx | Semi expanded |
x | Expanded |
ex | Extra expanded |
ux | Ultra expanded |
When forming the series string from the weight and width, drop the
m
that stands for medium weight or medium width, unless both
weight and width are m
, in which case use just one
(‘m
’).
\fontshape{shape}
¶Select font shape. Valid shapes are:
n | Upright (normal) |
it | Italic |
sl | Slanted (oblique) |
sc | Small caps |
ui | Upright italics |
ol | Outline |
The two last shapes are not available for most font families, and small caps are often missing as well.
\fontsize{size}{skip}
¶Set the font size and the line spacing. The unit of both parameters
defaults to points (pt
). The line spacing is the nominal
vertical space between lines, baseline to baseline. It is stored in the
parameter \baselineskip
. The default \baselineskip
for
the Computer Modern typeface is 1.2 times the \fontsize
.
Changing \baselineskip
directly is inadvisable since its value is
reset every time a size change happens; instead use
\baselinestretch
. (see \baselineskip
& \baselinestretch
).
\linespread{factor}
¶Equivalent to \renewcommand{\baselinestretch}{factor}
,
and therefore must be followed by \selectfont
to have any
effect. Best specified in the preamble. See \baselineskip
& \baselinestretch
, for using setspace
package instead.
\selectfont
¶The effects of the font commands described above do not happen until
\selectfont
is called, as in
\fontfamily{familyname}\selectfont
. It is often useful
to put this in a macro:
\newcommand*{\myfont}{\fontfamily{familyname}\selectfont}
(see \newcommand
& \renewcommand
).
\usefont{enc}{family}{series}{shape}
¶The same as invoking \fontencoding
, \fontfamily
,
\fontseries
and \fontshape
with the given parameters,
followed by \selectfont
. For example:
\usefont{ot1}{cmr}{m}{n}
Commands for controlling the general page layout.
\onecolumn
\twocolumn
\flushbottom
\raggedbottom
\baselineskip
& \baselinestretch
\onecolumn
¶Synopsis:
\onecolumn
Start a new page and produce single-column output. If the document is
given the class option onecolumn
then this is the default
behavior (see Document class options). This command is fragile
(see \protect
).
\twocolumn
¶Synopses:
\twocolumn \twocolumn[prelim one column text]
Start a new page and produce two-column output. If the document is given
the class option twocolumn
then this is the default
(see Document class options). This command is fragile
(see \protect
).
If the optional prelim one column text argument is present, it is typeset in one-column mode before the two-column typesetting starts.
These parameters control typesetting in two-column output:
\columnsep
¶The distance between columns. The default is 35pt. Change it with a
command such as \setlength{\columnsep}{40pt}
. You must change
it before the two column mode starts; in the preamble is a good
place.
\columnseprule
¶The width of the rule between columns. The default is 0pt, meaning that
there is no rule. Otherwise, the rule appears halfway between the two
columns. Change it with a command such as
\setlength{\columnseprule}{0.4pt}
, before the two-column
mode starts.
\columnwidth
¶The width of a single column. In one-column mode this is equal to
\textwidth
. In two-column mode by default LaTeX sets the
width of each of the two columns, \columnwidth
, to be half of
\textwidth
minus \columnsep
.
In a two-column document, the starred environments table*
and
figure*
are two columns wide, whereas the unstarred environments
table
and figure
take up only one column (see figure
and see table
). LaTeX places starred floats at the top of a page.
The following parameters control float behavior of two-column output.
\dbltopfraction
¶The maximum fraction at the top of a two-column page that may be
occupied by two-column wide floats. The default is 0.7, meaning that
the height of a table*
or figure*
environment must not
exceed 0.7\textheight
. If the height of your starred float
environment exceeds this then you can take one of the following actions
to prevent it from floating all the way to the back of the document:
[tp]
location specifier to tell LaTeX to try to put
the bulky float on a page by itself, as well as at the top of a page.
[t!]
location specifier to override the effect of
\dbltopfraction
for this particular float.
\dbltopfraction
to a suitably large number,
to avoid going to float pages so soon.
You can redefine it, as with
\renewcommand{\dbltopfraction}{0.9}
.
\dblfloatpagefraction
¶For a float page of two-column wide floats, this is the minimum fraction
that must be occupied by floats, limiting the amount of blank space.
LaTeX’s default is 0.5
. Change it with \renewcommand
.
\dblfloatsep
¶On a float page of two-column wide floats, this length is the distance
between floats, at both the top and bottom of the page. The default is
12pt plus2pt minus2pt
for a document set at 10pt
or
11pt
, and 14pt plus2pt minus4pt
for a document set at
12pt
.
\dbltextfloatsep
¶This length is the distance between a multi-column float at the top or
bottom of a page and the main text. The default is 20pt plus2pt
minus4pt
.
\dbltopnumber
¶On a float page of two-column wide floats, this counter gives the
maximum number of floats allowed at the top of the page. The LaTeX
default is 2
.
This example uses \twocolumn
’s optional argument of to create a
title that spans the two-column article:
\documentclass[twocolumn]{article} \newcommand{\authormark}[1]{\textsuperscript{#1}} \begin{document} \twocolumn[{% inside this optional argument goes one-column text \centering \LARGE The Title \\[1.5em] \large Author One\authormark{1}, Author Two\authormark{2}, Author Three\authormark{1} \\[1em] \normalsize \begin{tabular}{p{.2\textwidth}@{\hspace{2em}}p{.2\textwidth}} \authormark{1}Department one &\authormark{2}Department two \\ School one &School two \end{tabular}\\[3em] % space below title part }] Two column text here.
\flushbottom
¶Make all pages in the document after this declaration have the same height, by stretching the vertical space where necessary to fill out the page. This is most often used when making two-sided documents since the differences in facing pages can be glaring.
If TeX cannot satisfactorily stretch the vertical space in a page
then you get a message like ‘Underfull \vbox (badness 10000) has
occurred while \output is active’. If you get that, one option is to
change to \raggedbottom
(see \raggedbottom
). Alternatively,
you can adjust the textheight
to make compatible pages, or you
can add some vertical stretch glue between lines or between paragraphs,
as in \setlength{\parskip}{0ex plus0.1ex}
. Your last option
is to, in a final editing stage, adjust the height of individual pages
(see \enlargethispage
).
The \flushbottom
state is the default only if you select the
twocolumn
document class option (see Document class options),
and for indexes made using makeidx
.
\raggedbottom
¶Make all later pages the natural height of the material on that page; no
rubber vertical lengths will be stretched. Thus, in a two-sided
document the facing pages may be different heights. This command can go
at any point in the document body. See \flushbottom
.
This is the default unless you select the twocolumn
document class
option (see Document class options).
\columnsep
¶\columnseprule
¶\columnwidth
¶The distance between the two columns, the width of a rule between the
columns, and the width of the columns, when the document class option
twocolumn
is in effect (see Document class options).
See \twocolumn
.
\headheight
¶Height of the box that contains the running head. The default in the
article
, report
, and book
classes is ‘12pt’,
at all type sizes.
\headsep
¶Vertical distance between the bottom of the header line and the top of
the main text. The default in the article
and report
classes is ‘25pt’. In the book
class the default is: if the
document is set at 10pt then it is ‘0.25in’, and at 11pt or 12pt
it is ‘0.275in’.
\footskip
¶Distance from the baseline of the last line of text to the baseline of
the page footer. The default in the article
and report
classes is ‘30pt’. In the book
class the default is: when
the type size is 10pt the default is ‘0.35in’, while at 11pt it is
‘0.38in’, and at 12pt it is ‘30pt’.
\linewidth
¶Width of the current line, decreased for each nested list
(see list
). That is, the nominal value for \linewidth
is to
equal \textwidth
but for each nested list the \linewidth
is decreased by the sum of that list’s \leftmargin
and
\rightmargin
(see itemize
).
\marginparpush
¶\marginsep
¶\marginparwidth
¶The minimum vertical space between two marginal notes, the horizontal space between the text body and the marginal notes, and the horizontal width of the notes.
Normally marginal notes appear on the outside of the page, but the
declaration \reversemarginpar
changes that (and
\normalmarginpar
changes it back).
The defaults for \marginparpush
in both book
and
article
classes are: ‘7pt’ if the document is set at 12pt,
and ‘5pt’ if the document is set at 11pt or 10pt.
For \marginsep
, in article
class the default is
‘10pt’ except if the document is set at 10pt and in two-column mode
where the default is ‘11pt’.
For \marginsep
in book
class the default is ‘10pt’ in
two-column mode and ‘7pt’ in one-column mode.
For \marginparwidth
in both book
and article
classes, in two-column mode the default is 60% of \paperwidth
− \textwidth
, while in one-column mode it is 50% of that
distance.
\oddsidemargin
¶\evensidemargin
¶The \oddsidemargin
length is the extra distance between the left side of
the page and the text’s left margin, on odd-numbered pages when the
document class option twoside
is chosen and on all pages when
oneside
is in effect. When twoside
is in effect, on
even-numbered pages the extra distance on the left is
\evensidemargin
.
LaTeX’s default is that \oddsidemargin
is 40% of the
difference between \paperwidth
and \textwidth
, and
\evensidemargin
is the remainder.
\paperheight
¶The height of the paper, as distinct from the height of the print area.
Normally set with a document class option, as in
\documentclass[a4paper]{article}
(see Document class options).
\paperwidth
¶The width of the paper, as distinct from the width of the print area.
Normally set with a document class option, as in
\documentclass[a4paper]{article}
(see Document class options).
\textheight
¶The normal vertical height of the page body. If the document is set at
a nominal type size of 10pt then for an article
or report
the default is ‘43\baselineskip’, while for a book
it is
‘41\baselineskip’. At a type size of 11pt the default is
‘38\baselineskip’ for all document classes. At 12pt it is
‘36\baselineskip’ for all classes.
\textwidth
¶The full horizontal width of the entire page body. For an
article
or report
document, the default is ‘345pt’
when the chosen type size is 10pt, the default is ‘360pt’ at 11pt,
and it is ‘390pt’ at 12pt. For a book
document, the default
is ‘4.5in’ at a type size of 10pt, and ‘5in’ at 11pt or 12pt.
In multi-column output, \textwidth
remains the width of the
entire page body, while \columnwidth
is the width of one column
(see \twocolumn
).
In lists (see list
), \textwidth
remains the width of the
entire page body (and \columnwidth
the width of the entire
column), while \linewidth
may decrease for nested lists.
Inside a minipage (see minipage
) or \parbox
(see \parbox
), all the width-related parameters are set to the
specified width, and revert to their normal values at the end of the
minipage
or \parbox
.
\hsize
¶This entry is included for completeness: \hsize
is the TeX
primitive parameter used when text is broken into lines. It should not
be used in normal LaTeX documents.
\topmargin
¶Space between the top of the TeX page (one inch from the top of the
paper, by default) and the top of the header. The value is computed
based on many other parameters: \paperheight − 2in −
\headheight − \headsep − \textheight − \footskip
,
and then divided by two.
\topskip
¶Minimum distance between the top of the page body and the baseline of the first line of text. For the standard classes, the default is the same as the font size, e.g., ‘10pt’ at a type size of 10pt.
\baselineskip
& \baselinestretch
¶The \baselineskip
is a rubber length (see Lengths). It gives
the leading, the normal distance between lines in a paragraph, from
baseline to baseline.
Ordinarily document authors do not directly change \baselineskip
while writing. Instead, it is set by the low level font selection
command \fontsize
(see low level font commands fontsize).
The \baselineskip
’s value is reset every time a font change
happens and so any direct change to \baselineskip
would vanish
the next time there was a font switch. For how to influence line
spacing, see the discussion of \baselinestretch
below.
Usually, a font’s size and baseline skip is assigned by the font
designer. These numbers are nominal in the sense that if, for instance,
a font’s style file has the command \fontsize{10pt}{12pt}
then that does not mean that the characters in the font are 10pt tall;
for instance, parentheses and accented capitals may be taller. Nor does
it mean that if the lines are spaced less than 12pt apart then they risk
touching. Rather these numbers are typographic judgements. (Often, the
\baselineskip
is about twenty percent larger than the font size.)
The \baselineskip
is not a property of each line but of the
entire paragraph. As a result, large text in the middle of a paragraph,
such as a single {\Huge Q}
, will be squashed into its line.
TeX will make sure it doesn’t scrape up against the line above but
won’t change the \baselineskip
for that one line to make extra
room above. For the fix, use a \strut
(see \strut
).
The value of \baselineskip
that TeX uses for the paragraph is
the value in effect at the blank line or command that ends the paragraph
unit. So if a document contains this paragraph then its lines will be
scrunched together, compared to lines in surrounding paragraphs.
Many people see a page break between text and a displayed equation as bad style, so in effect the display is part of the paragraph. Because this display is in footnotesize, the entire paragraph has the baseline spacing matching that size. {\footnotesize $$a+b = c$$}
The process for making paragraphs is that when a new line is added, if
the depth of the previous line plus the height of the new line is less
than \baselineskip
then TeX inserts vertical glue to make up
the difference. There are two fine points. The first is that if the
lines would be too close together, closer than \lineskiplimit
,
then TeX instead uses \lineskip
as the interline glue. The
second is that TeX doesn’t actually use the depth of the previous
line. Instead it uses \prevdepth
, which usually contains that
depth. But at the beginning of the paragraph (or any vertical list) or
just after a rule, \prevdepth
has the value -1000pt and
this special value tells TeX not to insert any interline glue at the
paragraph start.
In the standard classes \lineskiplimit
is 0pt and
\lineskip
is 1pt. By the prior paragraph then, the distance
between lines can approach zero but if it becomes zero (or less than
zero) then the lines jump to 1pt apart.
Sometimes authors must, for editing purposes, put the document in
double space or one-and-a-half space. The right way to influence the
interline distance is via \baselinestretch
. It scales
\baselineskip
, and has a default value of 1.0. It is a
command, not a length, and does not take effect until a font change
happens, so set the scale factor like this:
\renewcommand{\baselinestretch}{1.5}\selectfont
.
The most straightforward way to change the line spacing for an entire
document is to put \linespread{factor}
in the preamble.
For double spacing, take factor to be 1.6 and for one-and-a-half
spacing use 1.3. These numbers are rough: for instance, since the
\baselineskip
is about 1.2 times the font size, multiplying by
1.6 gives a baseline skip to font size ratio of about 2. (The
\linespread
command is defined as
\renewcommand{\baselinestretch}{factor}
so it also
won’t take effect until a font setting happens. But that always takes
place at the start of a document, so there you don’t need to follow it
with \selectfont
.)
A simpler approach is the setspace
package. The basic example:
\usepackage{setspace} \doublespacing % or \onehalfspacing for 1.5
In the preamble these will start the document off with that sizing.
But you can also use these declarations in the document body to change
the spacing from that point forward, and consequently there is
\singlespacing
to return the spacing to normal. In the
document body, a better practice than using the declarations is to use
environments, such as \begin{doublespace}
... \end{doublespace}
. The package also has commands to do
arbitrary spacing: \setstretch{factor}
and
\begin{spacing}{factor} ... \end{spacing}
.
This package also keeps the line spacing single-spaced in places
where that is typically desirable, such as footnotes and figure
captions. See the package documentation.
Some typographic elements, such as figures and tables, cannot be broken across pages. They must be typeset outside of the normal flow of text, for instance floating to the top of a later page.
LaTeX can have a number of different classes of floating material.
The default is the two classes, figure
(see figure
) and
table
(see table
), but you can create a new class with the
package float
.
Within any one float class LaTeX always respects the order, so that the first figure in a document source must be typeset before the second figure. However, LaTeX may mix the classes, so it can happen that while the first table appears in the source before the first figure, it appears in the output after it.
The placement of floats is subject to parameters, given below, that limit the number of floats that can appear at the top of a page, and the bottom, etc. If so many floats are queued that the limits prevent them all from fitting on a page then LaTeX places what it can and defers the rest to the next page. In this way, floats may end up being typeset far from their place in the source. In particular, a float that is big may migrate to the end of the document. In which event, because all floats in a class must appear in sequential order, every following float in that class also appears at the end.
In addition to changing the parameters, for each float you can tweak
where the float placement algorithm tries to place it by using its
placement argument. The possible values are a sequence of the
letters below. The default for both figure
and table
, in
both article
and book
classes, is tbp
.
t
(Top)—at the top of a text page.
b
(Bottom)—at the bottom of a text page. (However, b
is not
allowed for full-width floats (figure*
) with double-column
output. To ameliorate this, use the stfloats or
dblfloatfix package, but see the discussion at caveats in the
FAQ: https://www.texfaq.org/FAQ-2colfloat.
h
(Here)—at the position in the text where the figure
environment
appears. However, h
is not allowed by itself; t
is
automatically added.
To absolutely force a float to appear “here”, you can
\usepackage{float}
and use the H
specifier which it
defines. For further discussion, see the FAQ entry at
https://www.texfaq.org/FAQ-figurehere.
p
¶(Page of floats)—on a separate float page, which is a page containing no text, only floats.
!
Used in addition to one of the above; for this float only, LaTeX
ignores the restrictions on both the number of floats that can appear
and the relative amounts of float and non-float text on the page.
The !
specifier does not mean “put the float here”;
see above.
Note: the order in which letters appear in the placement argument
does not change the order in which LaTeX tries to place the float;
for instance, btp
has the same effect as tbp
. All that
placement does is that if a letter is not present then the
algorithm does not try that location. Thus, LaTeX’s default of
tbp
is to try every location except placing the float where it
occurs in the source.
To prevent LaTeX from moving floats to the end of the document or a
chapter you can use a \clearpage
command to start a new page and
insert all pending floats. If a pagebreak is undesirable then you can
use the afterpage package and issue
\afterpage{\clearpage}
. This will wait until the current page
is finished and then flush all outstanding floats.
LaTeX can typeset a float before where it appears in the source
(although on the same output page) if there is a t
specifier in
the placement parameter. If this is not desired, and deleting
the t
is not acceptable as it keeps the float from being placed
at the top of the next page, then you can prevent it by either using
the flafter
package or using the command
\suppressfloats[t]
, which causes floats for the top position on
this page to moved to the next page.
Parameters relating to fractions of pages occupied by float and
non-float text (change them with
\renewcommand{parameter}{decimal between 0 and 1}
):
\bottomfraction
¶The maximum fraction of the page allowed to be occupied by floats at the bottom; default ‘.3’.
\floatpagefraction
¶The minimum fraction of a float page that must be occupied by floats; default ‘.5’.
\textfraction
¶Minimum fraction of a page that must be text; if floats take up too much space to preserve this much text, floats will be moved to a different page. The default is ‘.2’.
\topfraction
¶Maximum fraction at the top of a page that may be occupied before floats; default ‘.7’.
Parameters relating to vertical space around floats (change them with a
command of the form \setlength{parameter}{length
expression}
):
\floatsep
¶Space between floats at the top or bottom of a page; default ‘12pt plus2pt minus2pt’.
\intextsep
¶Space above and below a float in the middle of the main text; default ‘12pt plus2pt minus2pt’ for 10 point and 11 point documents, and ‘14pt plus4pt minus4pt’ for 12 point documents.
\textfloatsep
¶Space between the last (first) float at the top (bottom) of a page; default ‘20pt plus2pt minus4pt’.
Counters relating to the number of floats on a page (change them with a
command of the form \setcounter{ctrname}{natural
number}
):
bottomnumber
¶Maximum number of floats that can appear at the bottom of a text page; default 1.
dbltopnumber
¶Maximum number of full-sized floats that can appear at the top of a two-column page; default 2.
topnumber
¶Maximum number of floats that can appear at the top of a text page; default 2.
totalnumber
¶Maximum number of floats that can appear on a text page; default 3.
The principal TeX FAQ entry relating to floats https://www.texfaq.org/FAQ-floats contains suggestions for relaxing LaTeX’s default parameters to reduce the problem of floats being pushed to the end. A full explanation of the float placement algorithm is in Frank Mittelbach’s article “How to influence the position of float environments like figure and table in LaTeX?” (https://www.latex-project.org/publications/2014-FMi-TUB-tb111mitt-float-placement.pdf).
Structure your text into divisions: parts, chapters, sections, etc. All sectioning commands have the same form, one of:
sectioning-command{title} sectioning-command*{title} sectioning-command[toc-title]{title}
For instance, declare the start of a subsection as with
\subsection{Motivation}
.
The table has each sectioning-command in LaTeX. All are
available in all of LaTeX’s standard document classes book
,
report
, and article
, except that \chapter
is
not available in article
.
Sectioning unit | Command | Level |
---|---|---|
Part | \part | -1 (book , report ), 0 (article ) |
Chapter | \chapter | 0 |
Section | \section | 1 |
Subsection | \subsection | 2 |
Subsubsection | \subsubsection | 3 |
Paragraph | \paragraph | 4 |
Subparagraph | \subparagraph | 5 |
All these commands have a *
-form that prints title as usual
but does not number it and does not make an entry in the table of contents.
An example of using this is for an appendix in an article
. The
input \appendix\section{Appendix}
gives the output ‘A
Appendix’ (see \appendix
). You can lose the numbering ‘A’
by instead entering \section*{Appendix}
(articles often omit a
table of contents and have simple page headers so the other differences
from the \section
command may not matter).
The section title title provides the heading in the main text, but it may also appear in the table of contents and in the running head or foot (see Page styles). You may not want the same text in these places as in the main text. All of these commands have an optional argument toc-title for these other places.
The level number in the table above determines which sectional units are
numbered, and which appear in the table of contents. If the sectioning
command’s level is less than or equal to the value of the counter
secnumdepth
then the titles for this sectioning command will be
numbered (see Sectioning/secnumdepth). And, if level is less
than or equal to the value of the counter tocdepth
then the table
of contents will have an entry for this sectioning unit
(see Sectioning/tocdepth).
LaTeX expects that before you have a \subsection
you will have
a \section
and, in a book
class document, that before a
\section
you will have a \chapter
. Otherwise you can get
something like a subsection numbered ‘3.0.1’.
LaTeX lets you change the appearance of the sectional units. As a
simple example, you can change the section numbering to uppercase
letters with this (in the preamble):
\renewcommand\thesection{\Alph{section}}
.
(See \alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters.) CTAN
has many packages that make this adjustment easier, notably
titlesec
.
Two counters relate to the appearance of headings made by sectioning commands.
secnumdepth
¶Controls which sectioning unit are numbered. Setting the counter with
\setcounter{secnumdepth}{level}
will suppress
numbering of sectioning at any depth greater than level
(see \setcounter
). See the above table for the level numbers.
For instance, if the secnumdepth
is 1 in an article
then
a \section{Introduction}
command will produce output like
‘1 Introduction’ while \subsection{Discussion}
will
produce output like ‘Discussion’, without the number. LaTeX’s
default secnumdepth
is 3 in article class and
2 in the book and report classes.
tocdepth
¶Controls which sectioning units are listed in the table of contents.
The setting \setcounter{tocdepth}{level}
makes the
sectioning units at level be the smallest ones listed
(see \setcounter
). See the above table for the level numbers. For
instance, if tocdepth
is 1 then the table of contents will
list sections but not subsections. LaTeX’s default
tocdepth
is 3 in article class and 2 in the
book and report classes.
\part
\chapter
\section
\subsection
\subsubsection
, \paragraph
, \subparagraph
\appendix
\frontmatter
, \mainmatter
, \backmatter
\@startsection
: Typesetting sectional unit headings\part
¶Synopsis, one of:
\part{title} \part*{title} \part[toc-title]{title}
Start a document part. The standard LaTeX classes book
,
report
, and article
, all have this command.
This produces a document part, in a book.
\part{VOLUME I \\ PERSONAL MEMOIRS OF U.\ S.\ GRANT} \chapter{ANCESTRY--BIRTH--BOYHOOD.} My family is American, and has been for generations, in all its branches, direct and collateral.
In each standard class the \part
command outputs a part number
such as ‘Part I’, alone on its line, in boldface, and in large
type. Then LaTeX outputs title, also alone on its line, in
bold and in even larger type. In class book
, the LaTeX
default puts each part alone on its own page. If the book is two-sided
then LaTeX will skip a page if needed to have the new part on an
odd-numbered page. In report
it is again alone on a page, but
LaTeX won’t force it onto an odd-numbered page. In an article
LaTeX does not put it on a fresh page, but instead outputs the part
number and part title onto the main document page.
The *
form shows title
but it does not show the part number, does not increment the
part
counter, and produces no table of contents entry.
The optional argument toc-title will appear as the part title in the table of contents (see Table of contents, list of figures, list of tables) and in running headers (see Page styles). If it is not present then title will be there. This example puts a line break in title but omits the break in the table of contents.
\part[Up from the bottom; my life]{Up from the bottom\\ my life}
For determining which sectional units are numbered and which appear in the table of contents, the level number of a part is -1 (see Sectioning/secnumdepth, and Sectioning/tocdepth).
In the class article
, if a paragraph immediately follows the part
title then it is not indented. To get an indent you can use the package
indentfirst
.
One package to change the behavior of \part
is titlesec
.
See its documentation on CTAN.
\chapter
¶Synopsis, one of:
\chapter{title} \chapter*{title} \chapter[toc-title]{title}
Start a chapter. The standard LaTeX classes book
and
report
have this command but article
does not.
This produces a chapter.
\chapter{Loomings} Call me Ishmael. Some years ago---never mind how long precisely---having little or no money in my purse, and nothing particular to interest me on shore, I thought I would sail about a little and see the watery part of the world.
The LaTeX default starts each chapter on a fresh page, an
odd-numbered page if the document is two-sided. It produces a chapter
number such as ‘Chapter 1’ in large boldface type (the size is
\huge
). It then puts title on a fresh line, in boldface
type that is still larger (size \Huge
). It also increments the
chapter
counter, adds an entry to the table of contents
(see Table of contents, list of figures, list of tables), and sets the running header
information (see Page styles).
The *
form shows title on a fresh line, in boldface.
But it does not show the chapter number, does not increment the
chapter
counter, produces no table of contents entry, and does
not affect the running header. (If you use the page style
headings
in a two-sided document then the header will be from the
prior chapter.) This example illustrates.
\chapter*{Preamble}
The optional argument toc-title will appear as the chapter title in the table of contents (see Table of contents, list of figures, list of tables) and in running headers (see Page styles). If it is not present then title will be there. This shows the full name in the chapter title,
\chapter[Weyl]{Hermann Klaus Hugo (Peter) Weyl (1885--1955)}
but only ‘Weyl’ on the contents page. This puts a line break in the title but that doesn’t work well with running headers so it omits the break in the contents
\chapter[Given it all; my story]{Given it all\\ my story}
For determining which sectional units are numbered and which appear in the table of contents, the level number of a chapter is 0 (see Sectioning/secnumdepth and see Sectioning/tocdepth).
The paragraph that follows the chapter title is not indented, as is a
standard typographical practice. To get an indent use the package
indentfirst
.
You can change what is shown for the chapter number. To change it to
something like ‘Lecture 1’, put in the preamble either
\renewcommand{\chaptername}{Lecture}
or this
(see \makeatletter
& \makeatother
).
\makeatletter \renewcommand{\@chapapp}{Lecture} \makeatother
To make this change because of the primary language for
the document, see the package babel
.
In a two-sided document LaTeX puts a chapter on odd-numbered page, if
necessary leaving an even-numbered page that is blank except for any
running headers. To make that page completely blank,
see \clearpage
& \cleardoublepage
.
To change the behavior of the \chapter
command, you can copy its
definition from the LaTeX format file and make adjustments. But
there are also many packages on CTAN that address this. One is
titlesec
. See its documentation, but the example below gives a
sense of what it can do.
\usepackage{titlesec} % in preamble \titleformat{\chapter} {\Huge\bfseries} % format of title {} % label, such as 1.2 for a subsection {0pt} % length of separation between label and title {} % before-code hook
This omits the chapter number ‘Chapter 1’ from the page but unlike
\chapter*
it keeps the chapter in the table of contents and the
running headers.
\section
¶Synopsis, one of:
\section{title} \section*{title} \section[toc-title]{title}
Start a section. The standard LaTeX classes article
,
book
, and report
all have this command.
This produces a section.
In this Part we tend to be more interested in the function, in the input-output behavior, than in the details of implementing that behavior. \section{Turing machines} Despite this desire to downplay implementation, we follow the approach of A~Turing that the first step toward defining the set of computable functions is to reflect on the details of what mechanisms can do.
For the standard LaTeX classes book
and report
the
default output is like ‘1.2 title’ (for chapter 1,
section 2), alone on its line and flush left, in boldface and a
larger type (the type size is \Large
). The same holds in
article
except that there are no chapters in that class so it
looks like ‘2 title’.
The *
form shows title.
But it does not show the section number, does not increment the
section
counter, produces no table of contents entry, and does
not affect the running header. (If you use the page style
headings
in a two-sided document then the header will be from the
prior section.)
The optional argument toc-title will appear as the section title in the table of contents (see Table of contents, list of figures, list of tables) and in running headers (see Page styles). If it is not present then title will be there. This shows the full name in the title of the section:
\section[Elizabeth~II]{Elizabeth the Second, by the Grace of God of the United Kingdom, Canada and Her other Realms and Territories Queen, Head of the Commonwealth, Defender of the Faith.}
but only ‘Elizabeth II’ on the contents page and in the headers. This has a line break in title but that does not work with headers so it is omitted from the contents and headers.
\section[Truth is, I cheated; my life story]{Truth is, I cheated\\my life story}
For determining which sectional units are numbered and which appear in the table of contents, the level number of a section is 1 (see Sectioning/secnumdepth and see Sectioning/tocdepth).
The paragraph that follows the section title is not indented, as is a
standard typographical practice. One way to get an indent is to use the
package indentfirst
.
In general, to change the behavior of the \section
command, there
are a number of options. One is the \@startsection
command
(see \@startsection
: Typesetting sectional unit headings). There are also many packages on CTAN that
address this, including titlesec
. See the documentation but the
example below gives a sense of what they can do.
\usepackage{titlesec} % in preamble \titleformat{\section} {\normalfont\Large\bfseries} % format of title {\makebox[1pc][r]{\thesection\hspace{1pc}}} % label {0pt} % length of separation between label and title {} % before-code hook \titlespacing*{\section} {-1pc}{18pt}{10pt}[10pc]
That puts the section number in the margin.
\subsection
¶Synopsis, one of:
\subsection{title} \subsection*{title} \subsection[toc-title]{title}
Start a subsection. The standard LaTeX classes article
,
book
, and report
all have this command.
This produces a subsection.
We will show that there are more functions than Turing machines and that therefore some functions have no associated machine. \subsection{Cardinality} We will begin with two paradoxes that dramatize the challenge to our intuition posed by comparing the sizes of infinite sets.
For the standard LaTeX classes book
and report
the
default output is like ‘1.2.3 title’ (for chapter 1,
section 2, subsection 3), alone on its line and flush left, in
boldface and a larger type (the type size is \large
). The same
holds in article
except that there are no chapters in that class
so it looks like ‘2.3 title’.
The *
form shows title.
But it does not show the subsection number, does not increment the
subsection
counter, and produces no table of contents entry.
The optional argument toc-title will appear as the subsection title in the table of contents (see Table of contents, list of figures, list of tables). If it is not present then title will be there. This shows the full text in the title of the subsection:
\subsection[$\alpha,\beta,\gamma$ paper]{\textit{The Origin of Chemical Elements} by R.A.~Alpher, H.~Bethe, and G.~Gamow}
but only ‘α,β,γ paper’ on the contents page.
For determining which sectional units are numbered and which appear in the table of contents, the level number of a subsection is 2 (see Sectioning/secnumdepth and see Sectioning/tocdepth).
The paragraph that follows the subsection title is not indented, as is a
standard typographical practice. One way to get an indent is to use the
package indentfirst
.
There are a number of ways to change the behavior of the
\subsection
command. One is the \@startsection
command
(see \@startsection
: Typesetting sectional unit headings). There are also many packages on CTAN that
address this, including titlesec
. See the documentation but the
example below gives a sense of what they can do.
\usepackage{titlesec} % in preamble \titleformat{\subsection}[runin] {\normalfont\normalsize\bfseries} % format of the title {\thesubsection} % label {0.6em} % space between label and title {} % before-code hook
That puts the subsection number and title in the first line of text.
\subsubsection
, \paragraph
, \subparagraph
¶Synopsis, one of:
\subsubsection{title} \subsubsection*{title} \subsubsection[toc-title]{title}
or one of:
\paragraph{title} \paragraph*{title} \paragraph[toc-title]{title}
or one of:
\subparagraph{title} \subparagraph*{title} \subparagraph[toc-title]{title}
Start a subsubsection, paragraph, or subparagraph. The standard
LaTeX classes article
, book
, and report
all have
these commands, although they are not commonly used.
This produces a subsubsection.
\subsubsection{Piston ring compressors: structural performance} Provide exterior/interior wall cladding assemblies capable of withstanding the effects of load and stresses from consumer-grade gasoline engine piston rings.
The default output of each of the three does not change over the
standard LaTeX classes article
, book
, and
report
. For \subsubsection
the title is alone on
its line, in boldface and normal size type. For \paragraph
the
title is inline with the text, not indented, in boldface and
normal size type. For \subparagraph
the title is inline
with the text, with a paragraph indent, in boldface and normal size type
(Because an article
has no chapters its subsubsections are
numbered and so it looks like ‘1.2.3 title’, for
section 1, subsection 2, and subsubsection 3. The other
two divisions are not numbered.)
The *
form shows title. But it does not increment the
associated counter and produces no table of contents entry (and does not
show the number for \subsubsection
).
The optional argument toc-title will appear as the division title in the table of contents (see Table of contents, list of figures, list of tables). If it is not present then title will be there.
For determining which sectional units are numbered and which appear in the table of contents, the level number of a subsubsection is 3, of a paragraph is 4, and of a subparagraph is 5 (see Sectioning/secnumdepth and see Sectioning/tocdepth).
The paragraph that follows the subsubsection title is not indented, as is a
standard typographical practice. One way to get an indent is to use the
package indentfirst
.
There are a number of ways to change the behavior of the these commands.
One is the \@startsection
command (see \@startsection
: Typesetting sectional unit headings).
There are also many packages on CTAN that address this, including
titlesec
. See the documentation on CTAN.
\appendix
¶Synopsis:
\appendix
This does not directly produce any output. But in a book
or
report
document it declares that subsequent \chapter
commands start an appendix. In an article it does the same, for
\section
commands. It also resets the chapter
and
section
counters to 0 in a book or report, and in an article
resets the section
and subsection
counters.
In this book
\chapter{One} ... \chapter{Two} ... ... \appendix \chapter{Three} ... \chapter{Four} ...
the first two will generate output numbered ‘Chapter 1’ and
‘Chapter 2’. After the \appendix
the numbering will be
‘Appendix A’ and ‘Appendix B’. See Larger book
template,
for another example.
The appendix
package adds the command
\appendixpage
to put a separate ‘Appendices’ in the document
body before the first appendix, and the command \addappheadtotoc
to do the same in the table of contents. You can reset the name
‘Appendices’ with a command like
\renewcommand{\appendixname}{Specification}
, as well as a
number of other features. See the documentation on CTAN.
\frontmatter
, \mainmatter
, \backmatter
¶Synopsis, one or more of:
\frontmatter ... \mainmatter ... \backmatter ...
Format a book
class document differently according to which part
of the document is being produced. All three commands are optional.
Traditionally, a book’s front matter contains such things as the title page, an abstract, a table of contents, a preface, a list of notations, a list of figures, and a list of tables. (Some of these front matter pages, such as the title page, are traditionally not numbered.) The back matter may contain such things as a glossary, notes, a bibliography, and an index.
The \frontmatter
command makes the pages numbered in lowercase
roman, and makes chapters not numbered, although each chapter’s title
appears in the table of contents; if you use other sectioning commands
here, use the *
-version (see Sectioning).
The \mainmatter
command changes the behavior back to the expected
version, and resets the page number.
The \backmatter
command leaves the page numbering alone but
switches the chapters back to being not numbered.
See Larger book
template, for an example using these three commands.
\@startsection
: Typesetting sectional unit headings ¶Synopsis:
\@startsection{name}{level}{indent}{beforeskip}{afterskip}{style}
Used to help redefine the behavior of commands that start sectioning
divisions such as \section
or \subsection
.
The titlesec
package makes manipulation of sectioning
easier. Further, while most requirements for sectioning commands can be
satisfied with \@startsection
, some cannot. For instance, in
the standard LaTeX book
and report
classes the commands
\chapter
and \report
are not constructed using this. To
make such a command you may want to use the \secdef
command.
The \@startsection
macro is used like this:
\@startsection{name} {level} {indent} {beforeskip} {afterskip} {style}*[toctitle]{title}
so that issuing
\renewcommand{\section}{\@startsection{name} {level} {indent} {beforeskip} {afterskip} {style}}
redefines \section
while keeping its standard calling form
\section*[toctitle]{title}
(in which, as a reminder,
the star *
is optional). See Sectioning. This implies
that when you write a command like
\renewcommand{\section}{...}
, the
\@startsection{...}
must come last in the definition. See the
examples below.
Name of the counter used to number the sectioning header. This counter
must be defined separately. Most commonly this is either
section
, subsection
, or paragraph
. Although in
those cases the counter name is the same as the sectioning command
itself, you don’t have to use the same name.
Then \the
name displays the title number and
\
namemark
is for the page headers. See the third
example below.
An integer giving the depth of the sectioning command. See Sectioning, for the list of standard level numbers.
If level is less than or equal to the value of the counter
secnumdepth
then titles for this sectioning command will be
numbered (see Sectioning/secnumdepth). For instance, if
secnumdepth
is 1 in an article
then the command
\section{Introduction}
will produce output like “1
Introduction” while \subsection{Discussion}
will produce
output like “Discussion”, without the number prefix.
If level is less than or equal to the value of the counter
tocdepth then the table of contents will have an entry for this
sectioning unit (see Sectioning/tocdepth). For instance, in an
article
, if tocdepth is 1 then the table of contents will
list sections but not subsections.
A length giving the indentation of all of the title lines with respect
to the left margin. To have the title flush with the margin use
0pt
. A negative indentation such as -\parindent
will move
the title into the left margin.
The absolute value of this length is the amount of vertical space that
is inserted before this sectioning unit’s title. This space will be
discarded if the sectioning unit happens to start at the beginning of a
page. If this number is negative then the first paragraph following the
header is not indented; if it is non-negative then the first paragraph
is indented. (Example: the negative of 1pt plus 2pt minus 3pt
is -1pt plus -2pt minus -3pt
.)
For example, if beforeskip is -3.5ex plus -1ex minus -0.2ex
then to start the new sectioning unit, LaTeX will add about 3.5 times
the height of a letter x in vertical space, and the first paragraph in
the section will not be indented. Using a rubber length, with
plus
and minus
, is good practice here since it gives
LaTeX more flexibility in making up the page (see Lengths).
The full accounting of the vertical space between the baseline of the
line prior to this sectioning unit’s header and the baseline of the
header is that it is the sum of the \parskip
of the text font,
the \baselineskip
of the title font, and the absolute value of
the beforeskip. This space is typically rubber so it may stretch
or shrink. (If the sectioning unit starts on a fresh page so that the
vertical space is discarded then the baseline of the header text will be
where LaTeX would put the baseline of the first text line on that
page.)
This is a length. If afterskip is non-negative then this is the
vertical space inserted after the sectioning unit’s title header. If it
is negative then the title header becomes a run-in header, so that it
becomes part of the next paragraph. In this case the absolute value of
the length gives the horizontal space between the end of the title and
the beginning of the following paragraph. (Note that the negative of
1pt plus 2pt minus 3pt
is -1pt plus -2pt minus -3pt
.)
As with beforeskip, using a rubber length, with plus
and
minus
components, is good practice here since it gives LaTeX
more flexibility in putting together the page.
If afterskip
is non-negative then the full accounting of the
vertical space between the baseline of the sectioning unit’s header and
the baseline of the first line of the following paragraph is that it is
the sum of the \parskip
of the title font, the
\baselineskip
of the text font, and the value of after.
That space is typically rubber so it may stretch or shrink. (Note that
because the sign of afterskip
changes the sectioning unit
header’s from standalone to run-in, you cannot use a negative
afterskip
to cancel part of the \parskip
.)
Controls the styling of the title. See the examples below. Typical
commands to use here are \centering
, \raggedright
,
\normalfont
, \hrule
, or \newpage
. The last command
in style may be one that takes one argument, such as
\MakeUppercase
or \fbox
that takes one argument. The
section title will be supplied as the argument to this command. For
instance, setting style to \bfseries\MakeUppercase
would
produce titles that are bold and uppercase.
These are LaTeX’s defaults for the first three sectioning units that
are defined with \@startsection
, for the article,
book, and report classes.
section
: level is 1, indent is 0pt,
beforeskip is -3.5ex plus -1ex minus -0.2ex
,
afterskip is 2.3ex plus 0.2ex
, and style is
\normalfont\Large\bfseries
.
subsection
: level is 2, indent is 0pt,
beforeskip is -3.25ex plus -1ex minus -0.2ex
,
afterskip is 1.5ex plus 0.2ex
, and style is
\normalfont\large\bfseries
.
For subsubsection
: level is 3, indent is 0pt,
beforeskip is -3.25ex plus -1ex minus -0.2ex
,
afterskip is 1.5ex plus 0.2ex
, and style is
\normalfont\normalsize\bfseries
.
Some examples follow. These go either in a package or class file or in the
preamble of a LaTeX document. If you put them in the preamble they
must go between a \makeatletter
command and a
\makeatother
. (Probably the error message You can't use
`\spacefactor' in vertical mode.
means that you forgot this.)
See \makeatletter
& \makeatother
.
This will put section titles in large boldface type, centered. It says
\renewcommand
because LaTeX’s standard classes have already
defined a \section
. For the same reason it does not define a
section
counter, or the commands \thesection
and
\l@section
.
\renewcommand\section{% \@startsection{section}% name {1}% level {0pt}% indent {-3.5ex plus -1ex minus -.2ex}% beforeskip {2.3ex plus.2ex}% afterskip {\centering\normalfont\Large\bfseries}% style }
This will put subsection
titles in small caps type, inline with the paragraph.
\renewcommand\subsection{% \@startsection{subsection}% name {2}% level {0em}% indent {-1ex plus 0.1ex minus -0.05ex}% beforeskip {-1em plus 0.2em}% afterskip {\scshape}% style }
The prior examples redefined existing sectional unit title commands. This defines a new one, illustrating the needed counter and macros to display that counter.
\setcounter{secnumdepth}{6}% show counters this far down \newcounter{subsubparagraph}[subparagraph]% counter for numbering \renewcommand{\thesubsubparagraph}% how to display {\thesubparagraph.\@arabic\c@subsubparagraph}% numbering \newcommand{\subsubparagraph}{\@startsection {subsubparagraph}% {6}% {0em}% {\baselineskip}% {0.5\baselineskip}% {\normalfont\normalsize}} \newcommand*\l@subsubparagraph{\@dottedtocline{6}{10em}{5em}}% for toc \newcommand{\subsubparagraphmark}[1]{}% for page headers
We often want something like ‘See Theorem~31’. But by-hand typing
the 31 is poor practice. Instead you should write a label such as
\label{eq:GreensThm}
and then reference it, as with
See equation~\ref{eq:GreensThm}
. LaTeX will automatically
work out the number, put it into the output, and will change that number
later if needed.
We will see this with Theorem~\ref{th:GreensThm}. % forward reference ... \begin{theorem} \label{th:GreensThm} ... \end{theorem} ... See Theorem~\ref{th:GreensThm} on page~\pageref{th:GreensThm}.
LaTeX tracks cross reference information in a file having the
extension .aux and with the same base name as the file containing
the \label
. So if \label
is in calculus.tex then
the information is in calculus.aux. LaTeX puts the
information in that file every time it runs across a \label
.
The behavior described in the prior paragraph results in a quirk that
happens when your document has a forward reference, a \ref
that appears before the associated \label
. If this is the first
time that you are compiling the document then you will get ‘LaTeX
Warning: Label(s) may have changed. Rerun to get cross references right’
and in the output the forward reference will appear as two question
marks ‘??’, in boldface. A similar thing happens if you
change some things so the references changes; you get the same warning
and the output contains the old reference information. In both cases,
resolve this by compiling the document a second time.
The cleveref
package enhances LaTeX’s
cross referencing features. You can arrange that if you enter
\begin{thm}\label{th:Nerode}...\end{thm}
then
\cref{th:Nerode}
will output ‘Theorem 3.21’, without you
having to enter the “Theorem.”
\label
¶Synopsis:
\label{key}
Assign a reference number to key. In ordinary text
\label{key}
assigns to key the number of the
current sectional unit. Inside an environment with numbering, such as a
table
or theorem
environment, \label{key}
assigns to key the number of that environment. Retrieve the
assigned number with the \ref{key}
command
(see \ref
).
A key name can consist of any sequence of letters, digits, or common punctuation characters. Upper and lowercase letters are distinguished, as usual.
A common convention is to use labels consisting of a prefix and a suffix
separated by a colon or period. Thus, \label{fig:Post}
is a
label for a figure with a portrait of Emil Post. This helps to avoid
accidentally creating two labels with the same name, and makes your
source more readable. Some commonly-used prefixes:
ch
for chapters
sec
subsec
for lower-level sectioning commands
fig
for figures
tab
for tables
eq
for equations
In the auxiliary file the reference information is kept as the text of
a command of the form
\newlabel{label}{{currentlabel}{pagenumber}}
.
Here currentlabel is the current value of the macro
\@currentlabel
that is usually updated whenever you call
\refstepcounter{counter}
.
Below, the key sec:test
will get the number of the current
section and the key fig:test
will get the number of the figure.
(Incidentally, put labels after captions in figures and tables.)
\section{section name} \label{sec:test} This is Section~\ref{sec:test}. \begin{figure} ... \caption{caption text} \label{fig:test} \end{figure} See Figure~\ref{fig:test}.
\pageref
¶Synopsis:
\pageref{key}
Produce the page number of the place in the text where the corresponding
\label
{key} command appears.
If there is no \label{key}
then you get something like
‘LaTeX Warning: Reference `th:GrensThm' on page 1 undefined on
input line 11.’
Below, the \label{eq:main}
is used both for the formula number
and for the page number. (Note that the two references are forward
references so this document would need to be compiled twice to resolve
those.)
The main result is formula~\ref{eq:main} on page~\pageref{eq:main}. ... \begin{equation} \label{eq:main} \mathbf{P}=\mathbf{NP} \end{equation}
\ref
¶Synopsis:
\ref{key}
Produces the number of the sectional unit,
equation, footnote, figure, …, of the corresponding
\label
command (see \label
). It does not produce any text,
such as the word ‘Section’ or ‘Figure’, just the bare number itself.
If there is no \label{key}
then you get something like
‘LaTeX Warning: Reference `th:GrensThm' on page 1 undefined on
input line 11.’
In this example the \ref{popular}
produces ‘2’. Note that
it is a forward reference since it comes before \label{popular}
so this document would have to be compiled twice.
The most widely-used format is item number~\ref{popular}. \begin{enumerate} \item Plain \TeX \item \label{popular} \LaTeX \item Con\TeX t \end{enumerate}
The cleveref
package includes text such as ‘Theorem’ in the
reference. See the documentation on CTAN.
xr
package ¶Synopsis:
\usepackage{xr} \externaldocument{document-basename}
or
\usepackage{xr} \externaldocument[reference-prefix]{document-basename}
Make cross references to the external document document-basename.tex.
Here is an example. If lectures.tex has this in the preamble
\usepackage{xr} \externaldocument{exercises} \externaldocument[H-]{hints} \externaldocument{answers}
then it can use cross reference labels from the other three documents. Suppose that exercises.tex has an enumerated list containing this,
\item \label{exer:EulersThm} What if every vertex has odd degree?
and hints.tex has an enumerated list with this,
\item \label{exer:EulersThm} Distinguish the case of two vertices.
and answers.tex has an enumerated list with this,
\item \label{ans:EulersThm} There is no Euler path, except if there are exactly two vertices.
After compiling the exercises, hints, and answers documents, entering this in the body of lectures.tex will result in the lectures getting the reference numbers used in the other documents.
See Exercise~\ref{exer:EulersThm}, with Hint~\ref{H-exer:EulersThm}. The solution is Answer~\ref{ans:EulersThm}.
The prefix H-
for the reference from the hints file is needed
because the label in the hints file is the same as the label in the
exercises file. Without that prefix, both references would get the
number from the later file.
Note: if the document uses the hyperref
package then in place of
xr
, put \usepackage{xr-hyper}
before the
\usepackage{hyperref}
. Also, if any of the multiple documents
uses hyperref
then they all must use it.
LaTeX provides many environments for delimiting certain behavior.
An environment begins with \begin
and ends with \end
,
like this:
\begin{environment-name} ... \end{environment-name}
The environment-name at the beginning must exactly match that at
the end. For instance, the input
\begin{table*}...\end{table}
will cause an error like:
‘! LaTeX Error: \begin{table*} on input line 5 ended by
\end{table}.’
Environments are executed within a group.
abstract
array
center
description
displaymath
document
enumerate
eqnarray
equation
figure
filecontents
flushleft
flushright
itemize
letter
environment: writing letterslist
math
minipage
picture
quotation
& quote
tabbing
table
tabular
thebibliography
theorem
titlepage
verbatim
verse
abstract
¶Synopsis:
\begin{abstract} ... \end{abstract}
Produce an abstract, possibly of multiple paragraphs. This environment
is only defined in the article
and report
document classes
(see Document classes).
Using the example below in the article
class produces a displayed
paragraph. Document class option titlepage
causes the abstract
to be on a separate page (see Document class options); this is the
default only in the report
class.
\begin{abstract} We compare all known accounts of the proposal made by Porter Alexander to Robert E Lee at the Appomattox Court House that the army continue in a guerrilla war, which Lee refused. \end{abstract}
The next example produces a one column abstract in a two column document (for
a more flexible solution, use the package abstract
).
\documentclass[twocolumn]{article} ... \begin{document} \title{Babe Ruth as Cultural Progenitor: a Atavistic Approach} \author{Smith \\ Jones \\ Robinson\thanks{Railroad tracking grant.}} \twocolumn[ \begin{@twocolumnfalse} \maketitle \begin{abstract} Ruth was not just the Sultan of Swat, he was the entire swat team. \end{abstract} \end{@twocolumnfalse} ] { % by-hand insert a footnote at page bottom \renewcommand{\thefootnote}{\fnsymbol{footnote}} \footnotetext[1]{Thanks for all the fish.} }
array
¶Synopsis:
\begin{array}{cols} column 1 entry &column 2 entry ... &column n entry \\ ... \end{array}
or:
\begin{array}[pos]{cols} column 1 entry &column 2 entry ... &column n entry \\ ... \end{array}
Produce a mathematical array. This environment can only be used in math
mode (see Modes), and normally appears within a displayed
mathematics environment such as equation
(see equation
).
Inside of each row the column entries are separated by an ampersand,
(&
). Rows are terminated with double-backslashes (see \\
).
This example shows a three by three array.
\begin{equation*} \chi(x) = \left| % vertical bar fence \begin{array}{ccc} x-a &-b &-c \\ -d &x-e &-f \\ -g &-h &x-i \end{array} \right| \end{equation*}
The required argument cols describes the number of columns, their
alignment, and the formatting of the intercolumn regions. For instance,
\begin{array}{rcl}...\end{array}
gives three columns: the
first flush right, the second centered, and the third flush left. See
tabular
for the complete description of cols and of the
other common features of the two environments, including the optional
pos argument.
There are two ways that array
diverges from tabular
. The
first is that array
entries are typeset in math mode, in
textstyle (see Math styles) except if the cols definition specifies
the column with p{...}
, which causes the entry to be typeset in
text mode. The second is that, instead of tabular
’s parameter
\tabcolsep
, LaTeX’s intercolumn space in an array
is
governed by
\arraycolsep
, which gives half the width between columns. The
default for this is ‘5pt’ so that between two columns comes
10pt of space.
To obtain arrays with braces the standard is to use the amsmath
package. It comes with environments pmatrix
for an array
surrounded by parentheses (...)
, bmatrix
for an array
surrounded by square brackets [...]
, Bmatrix
for an
array surrounded by curly braces {...}
, vmatrix
for
an array surrounded by vertical bars |...|
, and
Vmatrix
for an array surrounded by double vertical
bars ||...||
, along with a number of other array constructs.
The next example uses the amsmath
package.
\usepackage{amsmath} % in preamble \begin{equation} \begin{vmatrix}{cc} % array with vert lines a &b \\ c &d \end{vmatrix}=ad-bc \end{equation}
There are many packages concerning arrays. The array
package has
many useful extensions, including more column types. The dcolumn
package adds a column type to center on a decimal point. For both see
the documentation on CTAN.
center
¶Synopsis:
\begin{center} line1 \\ line2 \\ ... \end{center}
Create a new paragraph consisting of a sequence of lines that are
centered within the left and right margins. Use
double-backslash, \\
, to get a line break (see \\
).
If some text is too long to fit on a line then LaTeX will insert line
breaks that avoid hyphenation and avoid stretching or shrinking any
interword space.
This environment inserts space above and below the text body. See
\centering
to avoid such space, for example inside a figure
environment.
This example produces three centered lines. There is extra vertical space between the last two lines.
\begin{center} A Thesis Submitted in Partial Fufillment \\ of the Requirements of \\[0.5ex] the School of Environmental Engineering \end{center}
In this example, depending on the page’s line width, LaTeX may choose a line break for the part before the double backslash. If so, it will center each of the two lines and if not it will center the single line. Then LaTeX will break at the double backslash, and will center the ending.
\begin{center} My father considered that anyone who went to chapel and didn't drink alcohol was not to be tolerated.\\ I grew up in that belief. ---Richard Burton \end{center}
A double backslash after the final line is optional. If present it doesn’t add any vertical space.
In a two-column document the text is centered in a column, not in the entire page.
\centering
¶Synopsis:
{\centering ... }
or
\begin{group} \centering ... \end{group}
Center the material in its scope. It is most often used inside an
environment such as figure
, or in a parbox
.
This example’s \centering
declaration causes the graphic to be
horizontally centered.
\begin{figure} \centering \includegraphics[width=0.6\textwidth]{ctan_lion.png} \caption{CTAN Lion} \label{fig:CTANLion} \end{figure}
The scope of this \centering
ends with the \end{figure}
.
Unlike the center
environment, the \centering
command does
not add vertical space above and below the text. That’s its advantage
in the above example; there is not an excess of space.
It also does not start a new paragraph; it simply changes how LaTeX
formats paragraph units. If ww {\centering xx \\ yy} zz
is
surrounded by blank lines then LaTeX will create a paragraph whose
first line ‘ww xx’ is centered and whose second line, not centered,
contains ‘yy zz’. Usually what is desired is for the scope of the
declaration to contain a blank line or the \end
command of an
environment such as figure
or table
that ends the
paragraph unit. Thus, if {\centering xx \\ yy\par} zz
is
surrounded by blank lines then it makes a new paragraph with two
centered lines ‘xx’ and ‘yy’, followed by a new paragraph with
‘zz’ that is formatted as usual.
description
¶Synopsis:
\begin{description} \item[label of first item] text of first item \item[label of second item] text of second item ... \end{description}
Environment to make a list of labeled items. Each item’s label is typeset in bold and is flush left, so that long labels continue into the first line of the item text. There must be at least one item; having none causes the LaTeX error ‘Something's wrong--perhaps a missing \item’.
This example shows the environment used for a sequence of definitions.
\begin{description} \item[lama] A priest. \item[llama] A beast. \end{description}
The labels ‘lama’ and ‘llama’ are output in boldface, with the left edge on the left margin.
Start list items with the \item
command (see \item
: An entry in a list). Use the
optional labels, as in \item[Main point]
, because there is
no sensible default. Following the \item
is optional text, which
may contain multiple paragraphs.
Since the labels are in bold style, if the label text calls for a font
change given in argument style (see Font styles) then it will come
out bold. For instance, if the label text calls for typewriter with
\item[\texttt{label text}]
then it will appear in bold
typewriter, if that is available. The simplest way around this, in this
example to get non-bold typewriter, is to use declarative style:
\item[{\tt label text}]
. Similarly, get the standard roman
font with \item[{\rm label text}]
.
For other major LaTeX labelled list environments, see itemize
and enumerate
. Unlike those environments, nesting
description
environments does not change the default label; it is
boldface and flush left at all levels.
For information about list layout parameters, including the default
values, and for information about customizing list layout, see
list
. The package enumitem
is useful for customizing
lists.
This example changes the description labels to small caps.
\renewcommand{\descriptionlabel}[1]{% {\hspace{\labelsep}\textsc{#1}}}
displaymath
¶Synopsis:
\begin{displaymath} mathematical text \end{displaymath}
Environment to typeset the mathematical text on its own line, in
display style and centered. To make the text be flush-left use the
global option fleqn
; see Document class options.
In the displaymath
environment no equation number is added to the
math text. One way to get an equation number is to use the
equation
environment (see equation
).
LaTeX will not break the math text across lines.
Note that the amsmath
package has significantly more extensive
displayed equation facilities. For example, there are a number of
ways in that package for having math text broken across lines.
The construct \[ math \]
is a synonym for the environment
\begin{displaymath} math \end{displaymath}
but the
latter is easier to work with in the source; for instance,
searching for a square bracket may get false positives but the word
displaymath
will likely be unique.
The construct $$math$$
from Plain TeX is
sometimes used as a synonym for LaTeX’s displaymath
. It is
not a synonym, and is not officially supported in LaTeX at all;
$$
doesn’t support the fleqn
option (see Document class options), has different vertical spacing, and doesn’t perform
consistency checks.
The output from this example is centered and alone on its line.
\begin{displaymath} \int_1^2 x^2\,dx=7/3 \end{displaymath}
Also, the integral sign is larger than the inline version
\( \int_1^2 x^2\,dx=7/3 \)
produces.
document
¶The document
environment encloses the entire body of a document.
It is required in every LaTeX document. See Starting and ending.
\AtBeginDocument
¶Synopsis:
\AtBeginDocument{code}
Save code and execute it when \begin{document}
is
executed, at the very end of the preamble. The code is executed after
the font selection tables have been set up, so the normal font for the
document is the current font. However, the code is executed as part of
the preamble so you cannot do any typesetting with it.
You can issue this command more than once; the successive code lines will be executed in the order that you gave them.
\AtEndDocument
¶Synopsis:
\AtEndDocument{code}
Save code and execute it near the end of the document.
Specifically, it is executed when \end{document}
is executed,
before the final page is finished and before any leftover floating
environments are processed. If you want some of the code to be executed
after these two processes then include a \clearpage
at the
appropriate point in code.
You can issue this command more than once; the successive code lines will be executed in the order that you gave them.
enumerate
¶Synopsis:
\begin{enumerate} \item[optional label of first item] text of first item \item[optional label of second item] text of second item ... \end{enumerate}
Environment to produce a numbered list of items. The format of the
label numbering depends on the nesting level of this environment; see
below. The default top-level numbering is ‘1.’, ‘2.’,
etc. Each enumerate
list environment must have at least one item;
having none causes the LaTeX error ‘Something's wrong--perhaps a
missing \item’.
This example gives the first two finishers in the 1908 Olympic marathon. As a top-level list the labels would come out as ‘1.’ and ‘2.’.
\begin{enumerate} \item Johnny Hayes (USA) \item Charles Hefferon (RSA) \end{enumerate}
Start list items with the \item
command (see \item
: An entry in a list). If you
give \item
an optional argument by following it with square
brackets, as in \item[Interstitial label]
, then the next item
will continue the interrupted sequence (see \item
: An entry in a list). That is, you
will get labels like ‘1.’, then ‘Interstitial label’, then
‘2.’. Following the \item
is optional text, which may
contain multiple paragraphs.
Enumerations may be nested within other enumerate
environments,
or within any paragraph-making environment such as itemize
(see itemize
), up to four levels deep. This gives LaTeX’s
default for the format at each nesting level, where 1 is the top level,
the outermost level.
The enumerate
environment uses the counters \enumi
through
\enumiv
(see Counters).
For other major LaTeX labeled list environments, see
description
and itemize
. For information about list layout
parameters, including the default values, and for information about
customizing list layout, see list
. The package enumitem
is
useful for customizing lists.
To change the format of the label use \renewcommand
(see \newcommand
& \renewcommand
) on the commands \labelenumi
through \labelenumiv
. For instance, this first level list will be
labelled with uppercase letters, in boldface, and without a trailing
period.
\renewcommand{\labelenumi}{\textbf{\Alph{enumi}}} \begin{enumerate} \item Shows as boldface A \item Shows as boldface B \end{enumerate}
For a list of counter-labeling commands see \alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters.
eqnarray
¶The eqnarray
environment is obsolete. It has infelicities,
including spacing that is inconsistent with other mathematics elements.
(See “Avoid eqnarray!” by Lars Madsen
https://tug.org/TUGboat/tb33-1/tb103madsen.pdf). New documents
should include the amsmath
package and use the displayed
mathematics environments provided there, such as the align
environment. We include a description only for completeness and for
working with old documents.
Synopsis:
\begin{eqnarray} first formula left &first formula middle &first formula right \\ ... \end{eqnarray}
or
\begin{eqnarray*} first formula left &first formula middle &first formula right \\ ... \end{eqnarray*}
Display a sequence of equations or inequalities. The left and right sides are typeset in display mode, while the middle is typeset in text mode.
It is similar to a three-column array
environment, with items
within a row separated by an ampersand (&
), and with rows
separated by double backslash \\
).
The starred form of line break (\\*
) can also be used to separate
equations, and will disallow a page break there (see \\
).
The unstarred form eqnarray
places an equation number on every
line (using the equation
counter), unless that line contains a
\nonumber
command. The starred form eqnarray*
omits
equation numbering, while otherwise being the same.
The command \lefteqn
is used for splitting long formulas across
lines. It typesets its argument in display style flush left in a box of
zero width.
This example shows three lines. The first two lines make an inequality, while the third line has not entry on the left side.
\begin{eqnarray*} \lefteqn{x_1+x_2+\cdots+x_n} \\ &\leq &y_1+y_2+\cdots+y_n \\ &= &z+y_3+\cdots+y_n \end{eqnarray*}
equation
¶Synopsis:
\begin{equation} mathematical text \end{equation}
The same as a displaymath
environment (see displaymath
)
except that LaTeX puts an equation number flush to the right margin.
The equation number is generated using the equation
counter.
You should have no blank lines between \begin{equation}
and
\end{equation}
, or LaTeX will tell you that there is a
missing dollar sign.
The package amsmath
package has extensive displayed equation
facilities. New documents should include this package.
figure
¶Synopsis:
\begin{figure}[placement] figure body \caption[loftitle]{title} % optional \label{label} % optional \end{figure}
or:
\begin{figure*}[placement] figure body \caption[loftitle]{title} % optional \label{label} % optional \end{figure*}
Figures are for material that is not part of the normal text. An example is material that you cannot have split between two pages, such as a graphic. Because of this, LaTeX does not typeset figures in sequence with normal text but instead “floats” them to a convenient place, such as the top of a following page (see Floats).
The figure body can consist of imported graphics
(see Graphics), or text, LaTeX commands, etc. It is typeset in a
parbox
of width \textwidth
.
The possible values of placement are h
for ‘here’,
t
for ‘top’, b
for ‘bottom’, and p
for
‘on a separate page of floats’. For the effect of these options on
the float placement algorithm, see Floats.
The starred form figure*
is used when a document is in
double-column mode (see \twocolumn
). It produces a figure that
spans both columns, at the top of the page. To add the possibility of
placing at a page bottom see the discussion of placement b
in Floats.
The label is optional; it is used for cross references (see Cross references). The optional \caption
command specifies caption
text for the figure (see \caption
). By default it is numbered.
If loftitle is present, it is used in the list of figures
instead of title (see Table of contents, list of figures, list of tables).
This example makes a figure out of a graphic. LaTeX will place that graphic and its caption at the top of a page or, if it is pushed to the end of the document, on a page of floats.
\usepackage{graphicx} % in preamble ... \begin{figure}[t] \centering \includegraphics[width=0.5\textwidth]{CTANlion.png} \caption{The CTAN lion, by Duane Bibby} \end{figure}
filecontents
¶Synopsis:
\begin{filecontents}[option]{filename} text \end{filecontents}
or
\begin{filecontents*}[option]{filename} text \end{filecontents*}
Create a file named filename in the current directory (or the output directory, if specified; see output directory) and write text to it. By default, an existing file is not overwritten.
The unstarred version of the environment
filecontents
prefixes the content of the created file with a
header of TeX comments; see the example below. The starred
version filecontents*
does not include the header.
The possible options are:
force
¶overwrite
Overwrite an existing file.
noheader
¶Omit the header. Equivalent to using filecontents*
.
nosearch
¶Only check the current directory (and the output directory, if specified) for an existing file, not the entire search path.
These options were added in a 2019 release of LaTeX.
This environment can be used anywhere in the preamble, although it
often appears before the \documentclass
command. It is
commonly used to create a .bib
or other such data file from the
main document source, to make the source file self-contained.
Similarly, it can be used to create a custom style or class file,
again making the source self-contained.
For example, this document:
\documentclass{article} \begin{filecontents}{JH.sty} \newcommand{\myname}{Jim Hef{}feron} \end{filecontents} \usepackage{JH} \begin{document} Article by \myname. \end{document}
produces this file JH.sty:
%% LaTeX2e file `JH.sty' %% generated by the `filecontents' environment %% from source `test' on 2015/10/12. %% \newcommand{\myname}{Jim Hef{}feron}
flushleft
¶Synopsis:
\begin{flushleft} line1 \\ line2 \\ ... \end{flushleft}
An environment that creates a paragraph whose lines are flush to the
left-hand margin, and ragged right. If you have lines that are too long
then LaTeX will linebreak them in a way that avoids hyphenation and
stretching or shrinking interword spaces. To force a new line use a double
backslash, \\
. For the declaration form
see \raggedright
.
This creates a box of text that is at most 3 inches wide, with the text flush left and ragged right.
\noindent\begin{minipage}{3in} \begin{flushleft} A long sentence that will be broken by \LaTeX{} at a convenient spot. \\ And, a fresh line forced by the double backslash. \end{flushleft} \end{minipage}
\raggedright
¶Synopses:
{\raggedright ... }
or
\begin{environment} \raggedright ... \end{environment}
A declaration which causes lines to be flush to the left margin and
ragged right. It can be used inside an environment such as quote
or in a parbox
. For the environment form
see flushleft
.
Unlike the flushleft
environment, the \raggedright
command does not start a new paragraph; it only changes how LaTeX
formats paragraph units. To affect a paragraph unit’s format, the
scope of the declaration must contain the blank line or \end
command that ends the paragraph unit.
Here \raggedright
in each second column keeps LaTeX from
doing awkward typesetting to fit the text into the narrow column.
Note that \raggedright
is inside the curly braces
{...}
to delimit its effect.
\begin{tabular}{rp{2in}} Team alpha &{\raggedright This team does all the real work.} \\ Team beta &{\raggedright This team ensures that the water cooler is never empty.} \\ \end{tabular}
flushright
¶\begin{flushright} line1 \\ line2 \\ ... \end{flushright}
An environment that creates a paragraph whose lines are flush to the
right-hand margin and ragged left. If you have lines that are too long
to fit the margins then LaTeX will linebreak them in a way that
avoids hyphenation and stretching or shrinking inter-word spaces. To force a new
line use a double backslash, \\
. For the declaration form
see \raggedleft
.
For an example related to this environment, see flushleft
,
where one just have mutatis mutandis to replace flushleft
by
flushright
.
\raggedleft
¶Synopses:
{\raggedleft ... }
or
\begin{environment} \raggedleft ... \end{environment}
A declaration which causes lines to be flush to the right margin and
ragged left. It can be used inside an environment such as quote
or in a parbox
. For the environment form
see flushright
.
Unlike the flushright
environment, the \raggedleft
command does not start a new paragraph; it only changes how LaTeX
formats paragraph units. To affect a paragraph unit’s formatting, the
scope of the declaration must contain the blank line or \end
command that ends the paragraph unit.
See \raggedright
, for an example related to this environment;
just replace \raggedright
there by \raggedleft
.
itemize
¶Synopsis:
\begin{itemize} \item[optional label of first item] text of first item \item[optional label of second item] text of second item ... \end{itemize}
Produce an unordered list, sometimes called a bullet list. There
must be at least one \item
within the environment; having none causes the
LaTeX error ‘Something's wrong--perhaps a missing \item’.
This gives a two-item list.
\begin{itemize} \item Pencil and watercolor sketch by Cassandra \item Rice portrait \end{itemize}
With the default locale—without loading e.g. babel
package
with another language than USenglish—as a top-level list each label
would come out as a bullet, •. The format of the labeling
depends on the nesting level; see below.
Start list items with the \item
command (see \item
: An entry in a list). If you
give \item
an optional argument by following it with square
brackets, as in \item[Optional label]
, then by default
Optional label will appear in bold and be flush right, so it could
extend into the left margin. For labels that are flush left see the
description
environment. Following the \item
is the text of
the item, which may be empty or contain multiple paragraphs.
Unordered lists can be nested within one another, up to four levels deep.
They can also be nested within other paragraph-making environments, such
as enumerate
(see enumerate
).
The itemize
environment uses the commands \labelitemi
through \labelitemiv
to produce the default label (note the
convention of lowercase roman numerals at the end of the command names
that signify the nesting level). These are the default marks at each
level.
\textbullet
)
\normalfont\bfseries\textendash
)
\textasteriskcentered
)
\textperiodcentered
)
Change the labels with \renewcommand
. For instance, this makes
the first level use diamonds.
\renewcommand{\labelitemi}{$\diamond$}
The distance between the left margin of the enclosing environment and
the left margin of the itemize
list is determined by the
parameters \leftmargini
through \leftmarginvi
. (This also
uses the convention of using lowercase roman numerals a the end of the
command name to denote the nesting level.) The defaults are:
2.5em
in level 1 (2em
in two-column mode), 2.2em
in
level 2, 1.87em
in level 3, and 1.7em
in level 4, with
smaller values for more deeply nested levels.
For other major LaTeX labeled list environments, see
description
and enumerate
. The itemize
,
enumerate
and description
environment use the same list
layout parameters. For a description, including the default values, and
for information about customizing list layout, see list
. The
package enumitem
is useful for customizing lists.
This example greatly reduces the margin space for outermost itemized lists.
\setlength{\leftmargini}{1.25em} % default 2.5em
Especially for lists with short items, it may be desirable to elide
space between items. Here is an example defining an itemize*
environment with no extra spacing between items, or between paragraphs
within a single item (\parskip
is not list-specific,
see \parindent
& \parskip
):
\newenvironment{itemize*}% {\begin{itemize}% \setlength{\itemsep}{0pt}% \setlength{\parsep}{0pt}% \setlength{\parskip}{0pt}% }% {\end{itemize}}
letter
environment: writing letters ¶This environment is used for creating letters. See Letters.
list
¶Synopsis:
\begin{list}{labeling}{spacing} \item[optional label of first item] text of first item \item[optional label of second item] text of second item ... \end{list}
An environment for constructing lists.
Note that this environment does not typically appear in the document
body. Most lists created by LaTeX authors are the ones that come
standard: the description
, enumerate
, and itemize
environments (see description
, enumerate
, and itemize
).
Instead, the list
environment is most often used in macros. For
example, many standard LaTeX environments that do not immediately
appear to be lists are in fact constructed using list
, including
quotation
, quote
, and center
(see quotation
& quote
, see center
).
This uses the list
environment to define a new custom
environment.
\newcounter{namedlistcounter} % number the items \newenvironment{named} {\begin{list} {Item~\Roman{namedlistcounter}.} % labeling {\usecounter{namedlistcounter} % set counter \setlength{\leftmargin}{3.5em}} % set spacing } {\end{list}} \begin{named} \item Shows as ``Item~I.'' \item[Special label.] Shows as ``Special label.'' \item Shows as ``Item~II.'' \end{named}
The mandatory first argument labeling specifies the default
labeling of list items. It can contain text and LaTeX commands, as
above where it contains both ‘Item’ and ‘\Roman{…}’.
LaTeX forms the label by putting the labeling argument in a box
of width \labelwidth
. If the label is wider than that, the
additional material extends to the right. When making an instance of a
list
you can override the default labeling by giving \item
an
optional argument by including square braces and the text, as in the
above \item[Special label.]
; see \item
: An entry in a list.
The mandatory second argument spacing has a list of commands.
This list can be empty. A command that can go in here is
\usecounter{countername}
(see \usecounter
). Use this
to tell LaTeX to number the items using the given counter. The
counter will be reset to zero each time LaTeX enters the environment,
and the counter is incremented by one each time LaTeX encounters an
\item
that does not have an optional argument.
Another command that can go in spacing is
\makelabel
, which constructs the label box. By default it puts
the contents flush right. Its only argument is the label, which it
typesets in LR mode (see Modes). One example of changing its
definition is that to the above named
example, before the
definition of the environment add
\newcommand{\namedmakelabel}[1]{\textsc{#1}}
, and between
the \setlength
command and the parenthesis that closes the
spacing argument also add \let\makelabel\namedmakelabel
.
Then the labels will be typeset in small caps. Similarly, changing the
second code line to \let\makelabel\fbox
puts the labels inside a
framed box. Another example of the \makelabel
command is below,
in the definition of the redlabel
environment.
Also often in spacing are commands to redefine the spacing for the
list. Below are the spacing parameters with their default values.
(Default values for derived environments such as itemize
can be
different than the values shown here.) See also the figure that follows
the list. Each is a length (see Lengths). The vertical spaces are
normally rubber lengths, with plus
and minus
components,
to give TeX flexibility in setting the page. Change each with a
command such as \setlength{\itemsep}{2pt plus1pt minus1pt}
.
For some effects these lengths should be zero or negative.
\itemindent
¶Extra horizontal space indentation, beyond leftmargin
, of the
first line each item. Its default value is 0pt
.
\itemsep
¶Vertical space between items, beyond the \parsep
. The defaults
for the first three levels in LaTeX’s ‘article’, ‘book’,
and ‘report’ classes at 10 point size are: 4pt plus2pt
minus1pt
, \parsep
(that is, 2pt plus1pt minus1pt
), and
\topsep
(that is, 2pt plus1pt minus1pt
). The defaults at
11 point are: 4.5pt plus2pt minus1pt
, \parsep
(that is,
2pt plus1pt minus1pt
), and \topsep
(that is, 2pt
plus1pt minus1pt
). The defaults at 12 point are: 5pt plus2.5pt
minus1pt
, \parsep
(that is, 2.5pt plus1pt minus1pt
), and
\topsep
(that is, 2.5pt plus1pt minus1pt
).
\labelsep
¶Horizontal space between the label and text of an item.
The default for LaTeX’s ‘article’, ‘book’,
and ‘report’ classes is 0.5em
.
\labelwidth
¶Horizontal width. The box containing the label is nominally this wide.
If \makelabel
returns text that is wider than this then the first
line of the item will be indented to make room for this extra material.
If \makelabel
returns text of width less than or equal to
\labelwidth
then LaTeX’s default is that the label is typeset
flush right in a box of this width.
The left edge of the label box is
\leftmargin
+\itemindent
-\labelsep
-\labelwidth
from the left margin of the enclosing environment.
The default for LaTeX’s ‘article’, ‘book’, and
‘report’ classes at the top level is
\leftmargini
-\labelsep
, (which is 2em
in one column
mode and 1.5em
in two column mode). At the second level it is
\leftmarginii
-\labelsep
, and at the third level it is
\leftmarginiii
-\labelsep
. These definitions make the
label’s left edge coincide with the left margin of the enclosing
environment.
\leftmargin
¶Horizontal space between the left margin of the enclosing environment (or the left margin of the page if this is a top-level list), and the left margin of this list. It must be non-negative.
In the standard LaTeX document classes, a top-level list has this set
to the value of \leftmargini
, while a list that is nested inside
a top-level list has this margin set to \leftmarginii
. More
deeply nested lists get the values of \leftmarginiii
through
\leftmarginvi
. (Nesting greater than level five generates the
error message ‘Too deeply nested’.)
The defaults for the first three levels in LaTeX’s ‘article’,
‘book’, and ‘report’ classes are: \leftmargini
is
2.5em
(in two column mode, 2em
), \leftmarginii
is
2.2em
, and \leftmarginiii
is 1.87em
.
\listparindent
¶Horizontal space of additional line indentation, beyond
\leftmargin
, for second and subsequent paragraphs within a list
item. A negative value makes this an “outdent”. Its default value
is 0pt
.
\parsep
¶Vertical space between paragraphs within an item.
The defaults for the first three levels in LaTeX’s ‘article’,
‘book’, and ‘report’ classes at 10 point size are: 4pt
plus2pt minus1pt
, 2pt plus1pt minus1pt
, and 0pt
. The
defaults at 11 point size are: 4.5pt plus2pt minus1pt
,
2pt plus1pt minus1pt
, and 0pt
. The defaults at 12 point
size are: 5pt plus2.5pt minus1pt
, 2.5pt plus1pt
minus1pt
, and 0pt
.
\partopsep
¶Vertical space added, beyond \topsep
+\parskip
, to the top
and bottom of the entire environment if the list instance is preceded by
a blank line. (A blank line in the LaTeX source before the list
changes spacing at both the top and bottom of the list; whether the line
following the list is blank does not matter.)
The defaults for the first three levels in LaTeX’s ‘article’,
‘book’, and ‘report’ classes at 10 point size are: 2pt
plus1 minus1pt
, 2pt plus1pt minus1pt
, and 1pt plus0pt
minus1pt
. The defaults at 11 point are: 3pt plus1pt minus1pt
,
3pt plus1pt minus1pt
, and 1pt plus0pt minus1pt
). The
defaults at 12 point are: 3pt plus2pt minus3pt
, 3pt plus2pt
minus2pt
, and 1pt plus0pt minus1pt
.
\rightmargin
¶Horizontal space between the right margin of the list and the right
margin of the enclosing environment. Its default value is 0pt
.
It must be non-negative.
\topsep
¶Vertical space added to both the top and bottom of the list, in addition
to \parskip
(see \parindent
& \parskip
). The defaults for
the first three levels in LaTeX’s ‘article’, ‘book’, and
‘report’ classes at 10 point size are: 8pt plus2pt minus4pt
,
4pt plus2pt minus1pt
, and 2pt plus1pt minus1pt
. The
defaults at 11 point are: 9pt plus3pt minus5pt
, 4.5pt
plus2pt minus1pt
, and 2pt plus1pt minus1pt
. The defaults at 12
point are: 10pt plus4pt minus6pt
, 5pt plus2.5pt minus1pt
,
and 2.5pt plus1pt minus1pt
.
This shows the horizontal and vertical distances.
The lengths shown are listed below. The key relationship is that the right edge of the bracket for h1 equals the right edge of the bracket for h4, so that the left edge of the label box is at h3+h4-(h0+h1).
\topsep
+ \parskip
if
the list environment does not start a new paragraph, and
\topsep
+\parskip
+\partopsep
if it does
\parsep
\itemsep
+\parsep
Same as v0. (This space is affected by whether a blank line appears in the source above the environment; whether a blank line appears in the source below the environment does not matter.)
\labelwidth
\labelsep
\listparindent
\leftmargin
\itemindent
\rightmargin
The list’s left and right margins, shown above as h3 and h5,
are with respect to the ones provided by the surrounding environment, or
with respect to the page margins for a top-level list. The line width
used for typesetting the list items is \linewidth
(see Page layout parameters). For instance, set the list’s left margin to be one
quarter of the distance between the left and right margins of the
enclosing environment with
\setlength{\leftmargin}{0.25\linewidth}
.
Page breaking in a list structure is controlled by the three
parameters below. For each, the LaTeX default is
-\@lowpenalty
, that is, -51
. Because it is negative,
it somewhat encourages a page break at each spot. Change it with,
e.g., \@beginparpenalty=9999
; a value of 10000 prohibits a
page break.
\@beginparpenalty
¶The page breaking penalty for breaking before the list (default -51
).
\@itempenalty
¶The page breaking penalty for breaking before a list item (default -51
).
\@endparpenalty
¶The page breaking penalty for breaking after a list (default -51
).
The package enumitem
is useful for customizing lists.
This example has the labels in red. They are numbered, and the left
edge of the label lines up with the left edge of the item text.
See \usecounter
.
\usepackage{color} \newcounter{cnt} \newcommand{\makeredlabel}[1]{\textcolor{red}{#1.}} \newenvironment{redlabel} {\begin{list} {\arabic{cnt}} {\usecounter{cnt} \setlength{\labelwidth}{0em} \setlength{\labelsep}{0.5em} \setlength{\leftmargin}{1.5em} \setlength{\itemindent}{0.5em} % equals \labelwidth+\labelsep \let\makelabel=\makeredlabel } } {\end{list}}
\item
: An entry in a list ¶Synopsis:
\item text of item
or
\item[optional-label] text of item
An entry in a list. The entries are prefixed by a label, whose default depends on the list type.
Because the optional label is surrounded by square brackets
‘[...]’, if you have an item whose text starts with [, you
have to hide the bracket inside curly braces, as in: \item
{[} is an open square bracket
; otherwise, LaTeX will think it
marks the start of an optional label.
Similarly, if the item does have the optional label and you need a
close square bracket inside that label, you must hide it in the same
way: \item[Close square bracket, {]}]
. See LaTeX command syntax.
In this example the enumerate list has two items that use the default label and one that uses the optional label.
\begin{enumerate} \item Moe \item[sometimes] Shemp \item Larry \end{enumerate}
The first item is labelled ‘1.’, the second item is labelled ‘sometimes’, and the third item is labelled ‘2.’. Because of the optional label in the second item, the third item is not labelled ‘3.’.
trivlist
: A restricted form of list
¶Synopsis:
\begin{trivlist} ... \end{trivlist}
A restricted version of the list environment, in which margins are not
indented and an \item
without an optional argument produces no
text. It is most often used in macros, to define an environment where
the \item
command is part of the environment’s definition. For
instance, the center
environment is defined essentially like
this:
\newenvironment{center} {\begin{trivlist}\centering\item\relax} {\end{trivlist}}
Using trivlist
in this way allows the macro to inherit some
common code: combining vertical space of two adjacent environments;
detecting whether the text following the environment should be
considered a new paragraph or a continuation of the previous one;
adjusting the left and right margins for possible nested list
environments.
Specifically, trivlist
uses the current values of the list
parameters (see list
), except that \parsep
is set to the
value of \parskip
, and \leftmargin
, \labelwidth
,
and \itemindent
are set to zero.
This example outputs the items as two paragraphs, except that (by default) they have no paragraph indent and are vertically separated.
\begin{trivlist} \item The \textit{Surprise} is not old; no one would call her old. \item She has a bluff bow, lovely lines. \end{trivlist}
math
¶Synopsis:
\begin{math} math \end{math}
The math
environment inserts given math material within
the running text. \(...\)
and $...$
are synonyms.
See Math formulas.
minipage
¶Synopses:
\begin{minipage}{width} contents \end{minipage}
or
\begin{minipage}[position][height][inner-pos]{width} contents \end{minipage}
Put contents into a box that is width wide. This is like a
small version of a page; it can contain its own footnotes, itemized
lists, etc. (There are some restrictions, including that it cannot have
floats.) This box will not be broken across pages. So minipage
is similar to \parbox
(see \parbox
) but here you can have
paragraphs.
This example will be 3 inches wide, and has two paragraphs.
\begin{minipage}{3in} Stephen Kleene was a founder of the Theory of Computation. He was a student of Church, wrote three influential texts, was President of the Association for Symbolic Logic, and won the National Medal of Science. \end{minipage}
See below for a discussion of the paragraph indent inside a
minipage
.
The required argument width is a rigid length (see Lengths). It gives the width of the box into which contents are typeset.
There are three optional arguments, position, height, and
inner-pos. You need not include all three. For example, get the
default position and set the height with
\begin{minipage}[c][2.54cm]{\columnwidth} contents
\end{minipage}
. (Get the natural height with an empty argument,
[]
.)
The optional argument position governs how the minipage
vertically aligns with the surrounding material.
c
(synonym m
) Default. Positions the minipage
so its
vertical center lines up with the center of the adjacent text line.
t
¶Align the baseline of the top line in the minipage
with the
baseline of the surrounding text (plain TeX’s \vtop
).
b
¶Align the baseline of the bottom line in the minipage
with the
baseline of the surrounding text (plain TeX’s \vbox
).
To see the effects of these, contrast running this
---\begin{minipage}[c]{0.25in} first\\ second\\ third \end{minipage}
with the results of changing c
to b
or t
.
The optional argument height is a rigid length (see Lengths).
It sets the height of the minipage
. You can enter any value
larger than, or equal to, or smaller than the minipage
’s natural
height and LaTeX will not give an error or warning. You can also set
it to a height of zero or a negative value.
The final optional argument inner-pos controls the placement of contents inside the box. These are the possible values are (the default is the value of position).
t
Place contents at the top of the box.
c
Place it in the vertical center.
b
Place it at the box bottom.
s
Stretch contents out vertically; it must contain vertically stretchable space.
The inner-pos argument makes sense when the height option
is set to a value larger than the minipage
’s natural height. To
see the effect of the options, run this example with the various choices
in place of b
.
Text before \begin{center} ---\begin{minipage}[c][3in][b]{0.25\textwidth} first\\ second\\ third \end{minipage} \end{center} Text after
By default paragraphs are not indented in a minipage
. Change
that with a command such as \setlength{\parindent}{1pc}
at
the start of contents.
Footnotes in a minipage
environment are handled in a way that is
particularly useful for putting footnotes in figures or tables. A
\footnote
or \footnotetext
command puts the footnote at
the bottom of the minipage instead of at the bottom of the page, and it
uses the \mpfootnote
counter instead of the ordinary
footnote
counter (see Counters).
This puts the footnote at the bottom of the table, not the bottom of the page.
\begin{center} % center the minipage on the line \begin{minipage}{2.5in} \begin{center} % center the table inside the minipage \begin{tabular}{ll} \textsc{Monarch} &\textsc{Reign} \\ \hline Elizabeth II &63 years\footnote{to date} \\ Victoria &63 years \\ George III &59 years \end{tabular} \end{center} \end{minipage} \end{center}
If you nest minipages then there is an oddness when using footnotes.
Footnotes appear at the bottom of the text ended by the next
\end{minipage}
which may not be their logical place.
This puts a table containing data side by side with a map graphic. They are vertically centered.
% siunitx to have the S column specifier, % which aligns numbers on their decimal point. \usepackage{siunitx} \newcommand*{\vcenteredhbox}[1]{\begin{tabular}{@{}c@{}}#1\end{tabular}} ... \begin{center} \vcenteredhbox{\includegraphics[width=0.3\textwidth]{nyc.png}} \hspace{0.1\textwidth} \begin{minipage}{0.5\textwidth} \begin{tabular}{r|S} % \multicolumn to remove vertical bar between column headers \multicolumn{1}{r}{Borough} & % braces to prevent siunitx from misinterpreting the % period as a decimal separator {Pop. (million)} \\ \hline The Bronx &1.5 \\ Brooklyn &2.6 \\ Manhattan &1.6 \\ Queens &2.3 \\ Staten Island &0.5 \end{tabular} \end{minipage} \end{center}
picture
¶Synopses:
\begin{picture}(width,height) picture command \end{picture}
or
\begin{picture}(width,height)(xoffset,yoffset) picture command \end{picture}
Where there may be any number of picture command’s.
An environment to create simple pictures containing lines, arrows, boxes, circles, and text. This environment is not obsolete, but new documents typically use much more powerful graphics creation systems, such as TikZ, PSTricks, MetaPost, or Asymptote. None of these are covered in this document; see CTAN.
To start, here’s an example showing the parallelogram law for adding vectors.
\setlength{\unitlength}{1cm} \begin{picture}(6,6) % picture box will be 6cm wide by 6cm tall \put(0,0){\vector(2,1){4}} % for every 2 over this vector goes 1 up \put(2,1){\makebox(0,0)[l]{\ first leg}} \put(4,2){\vector(1,2){2}} \put(5,4){\makebox(0,0)[l]{\ second leg}} \put(0,0){\vector(1,1){6}} \put(3,3){\makebox(0,0)[r]{sum\ }} \end{picture}
The picture
environment has one required argument, a pair of
positive real numbers (width,height). Multiply these by the
value \unitlength
to get the nominal size of the output, i.e.
the space that LaTeX reserves on the output page. This nominal size
need not be how large the picture really is; LaTeX will draw things
from the picture outside the picture’s box.
This environment also has an optional argument
(xoffset,yoffset). It is used to shift the origin. Unlike
most optional arguments, this one is not contained in square brackets.
As with the required argument, it consists of a pair of two real
numbers, but these may also be negative or null. Multiply these
by \unitlength
to get the coordinates of the point at the
lower-left corner of the picture.
For example, if \unitlength
has been set to 1mm
, the
command
\begin{picture}(100,200)(10,20)
produces a box of width 100 millimeters and height 200 millimeters. The picture’s origin is the point (10mm,20mm) and so the lower-left corner is there, and the upper-right corner is at (110mm,220mm). When you first draw a picture you typically omit the optional argument, leaving the origin at the lower-left corner. If you then want to modify your picture by shifting everything, you can just add the appropriate optional argument.
Each picture command tells LaTeX where to put something by
providing its position. A position is a pair such as (2.4,-5)
giving the x- and y-coordinates. A coordinate is a not a length,
it is a real number (it may have a decimal point or a minus sign). It
specifies a length in multiples of the unit length \unitlength
,
so if \unitlength
has been set to 1cm
, then the coordinate
2.54
specifies a length of 2.54 centimeters.
LaTeX’s default for \unitlength
is 1pt
. It is a rigid
length (see Lengths). Change it with the \setlength
command
(see \setlength
). Make this change only outside of a picture
environment.
The picture
environment supports using standard arithmetic
expressions as well as numbers.
Coordinates are given with respect to an origin, which is by default at
the lower-left corner of the picture. Note that when a position appears
as an argument, as with \put(1,2){...}
, it is not enclosed in
braces since the parentheses serve to delimit the argument. Also,
unlike in some computer graphics systems, larger y-coordinates are
further up the page, for example, y = 1 is above y = 0.
There are four ways to put things in a picture: \put
,
\multiput
, \qbezier
, and \graphpaper
. The most
often used is \put
. This
\put(11.3,-0.3){...}
places the object with its reference point at coordinates
(11.3,-0.3). The reference points for various objects will be
described below.
The \put
command creates an LR box (see Modes).
Anything that can go in an \mbox
(see \mbox
& \makebox
) can
go in the text argument of the \put
command. The reference point
will be the lower left corner of the box. In this picture
\setlength{\unitlength}{1cm} ...\begin{picture}(1,1) \put(0,0){\line(1,0){1}} \put(0,0){\line(1,1){1}} \end{picture}
the three dots are just slightly left of the point of the angle formed
by the two lines. (Also, \line(1,1){1}
does not call for a
line of length one; rather the line has a change in the x coordinate of
1.)
The \multiput
, qbezier
, and graphpaper
commands are
described below.
You can also use this environment to place arbitrary material at an exact location. For example:
\usepackage{color,graphicx} % in preamble ... \begin{center} \setlength{\unitlength}{\textwidth} \begin{picture}(1,1) % leave space, \textwidth wide and tall \put(0,0){\includegraphics[width=\textwidth]{desertedisland.jpg}} \put(0.25,0.35){\textcolor{red}{X Treasure here}} \end{picture} \end{center}
The red X will be precisely a quarter of the \textwidth
from
the left margin, and 0.35\textwidth
up from the bottom of the
picture. Another example of this usage is to put similar code in the
page header to get repeat material on each of a document’s pages.
\put
\multiput
\qbezier
\graphpaper
\line
\linethickness
\thinlines
\thicklines
\circle
\oval
\shortstack
\vector
\makebox
(picture)\framebox
(picture)\frame
\dashbox
\put
¶Synopsis:
\put(xcoord,ycoord){content}
Place content at the coordinate (xcoord,ycoord). See
the discussion of coordinates and \unitlength
in picture
.
The content is processed in LR mode (see Modes) so it cannot
contain line breaks.
This includes the text into the picture
.
\put(4.5,2.5){Apply the \textit{unpoke} move}
The reference point, the location (4.5,2.5), is the lower left of the text, at the bottom left of the ‘A’.
\multiput
¶Synopsis:
\multiput(x,y)(delta_x,delta_y){num-copies}{obj}
Copy obj a total of num-copies times, with an increment of delta_x,delta_y. The obj first appears at position (x,y), then at (x+\delta_x,y+\delta_y), and so on.
This draws a simple grid with every fifth line in bold (see also
\graphpaper
).
\begin{picture}(10,10) \linethickness{0.05mm} \multiput(0,0)(1,0){10}{\line(0,1){10}} \multiput(0,0)(0,1){10}{\line(1,0){10}} \linethickness{0.5mm} \multiput(0,0)(5,0){3}{\line(0,1){10}} \multiput(0,0)(0,5){3}{\line(1,0){10}} \end{picture}
\qbezier
¶Synopsis:
\qbezier(x1,y1)(x2,y2)(x3,y3) \qbezier[num](x1,y1)(x2,y2)(x3,y3)
Draw a quadratic Bezier curve whose control points are given by the
three required arguments (x1,y1)
,
(x2,y2)
, and (x3,y3)
. That is,
the curve runs from (x1,y1) to (x3,y3), is quadratic, and is
such that the tangent line at (x1,y1) passes through
(x2,y2), as does the tangent line at (x3,y3).
This draws a curve from the coordinate (1,1) to (1,0).
\qbezier(1,1)(1.25,0.75)(1,0)
The curve’s tangent line at (1,1) contains (1.25,0.75), as does the curve’s tangent line at (1,0).
The optional argument num gives the number of calculated
intermediate points. The default is to draw a smooth curve whose
maximum number of points is \qbeziermax
(change this value with
\renewcommand
).
This draws a rectangle with a wavy top, using \qbezier
for
that curve.
\begin{picture}(8,4) \put(0,0){\vector(1,0){8}} % x axis \put(0,0){\vector(0,1){4}} % y axis \put(2,0){\line(0,1){3}} % left side \put(4,0){\line(0,1){3.5}} % right side \qbezier(2,3)(2.5,2.9)(3,3.25) \qbezier(3,3.25)(3.5,3.6)(4,3.5) \thicklines % below here, lines are twice as thick \put(2,3){\line(4,1){2}} \put(4.5,2.5){\framebox{Trapezoidal Rule}} \end{picture}
\graphpaper
¶Synopsis:
\graphpaper(x_init,y_init)(x_dimen,y_dimen) \graphpaper[spacing](x_init,y_init)(x_dimen,y_dimen)
Draw a coordinate grid. Requires the graphpap
package.
The grid’s origin is (x_init,y_init)
.
Grid lines come every spacing units (the default is 10).
The grid extends x_dimen units to the right and y_dimen units up.
All arguments must be positive integers.
This make a grid with seven vertical lines and eleven horizontal lines.
\usepackage{graphpap} % in preamble ... \begin{picture}(6,20) % in document body \graphpaper[2](0,0)(12,20) \end{picture}
The lines are numbered every ten units.
\line
¶Synopsis:
\line(x_run,y_rise){travel}
Draw a line. It slopes such that it vertically rises y_rise for every horizontal x_run. The travel is the total horizontal change—it is not the length of the vector, it is the change in x. In the special case of vertical lines, where (x_run,y_rise)=(0,1), the travel gives the change in y.
This draws a line starting at coordinates (1,3).
\put(1,3){\line(2,5){4}}
For every over 2, this line will go up 5. Because travel specifies that this goes over 4, it must go up 10. Thus its endpoint is (1,3)+(4,10)=(5,13). In particular, note that travel=4 is not the length of the line, it is the change in x.
The arguments x_run and y_rise are integers that can be
positive, negative, or zero. (If both are 0 then LaTeX treats the
second as 1.) With
\put(x_init,y_init){\line(x_run,y_rise){travel}}
,
if x_run is negative then the line’s ending point has a first
coordinate that is less than x_init. If y_rise is negative
then the line’s ending point has a second coordinate that is less than
y_init.
If travel is negative then you get LaTeX Error: Bad \line or
\vector argument.
Standard LaTeX can only draw lines with a limited range of slopes
because these lines are made by putting together line segments from
pre-made fonts. The two numbers x_run and y_rise must have
integer values from −6 through 6. Also, they must be
relatively prime, so that (x_run,y_rise) can be (2,1) but not
(4,2) (if you choose the latter then instead of lines you get sequences
of arrowheads; the solution is to switch to the former). To get lines
of arbitrary slope and plenty of other shapes in a system like
picture
, see the package pict2e
(https://ctan.org/pkg/pict2e). Another solution
is to use a full-featured graphics system such as TikZ, PSTricks,
MetaPost, or Asymptote.
\linethickness
¶Synopsis:
\linethickness{dim}
Declares the thickness of subsequent horizontal and vertical lines in a
picture to be dim, which must be a positive length
(see Lengths). It differs from \thinlines
and
\thicklines
in that it does not affect the thickness of slanted
lines, circles, or ovals (see \oval
).
\thinlines
¶Declaration to set the thickness of subsequent lines, circles, and ovals
in a picture environment to be 0.4pt. This is the default
thickness, so this command is unnecessary unless the thickness has been
changed with either \linethickness
or \thicklines
.
\thicklines
¶Declaration to set the thickness of subsequent lines, circles, and ovals
in a picture environment to be 0.8pt. See also
\linethickness
and \thinlines
. This command is illustrated
in the Trapezoidal Rule example of \qbezier
.
\circle
¶Synopsis:
\circle{diameter} \circle*{diameter}
Produces a circle with a diameter as close as possible to the specified
one. The *
form produces a filled-in circle.
This draws a circle of radius 6, centered at (5,7)
.
\put(5,7){\circle{6}}
The available radii for \circle
are, in points, the even
numbers from 2 to 20, inclusive. For \circle*
they are all the
integers from 1 to 15.
\oval
¶Synopsis:
\oval(width,height) \oval(width,height)[portion]
Produce a rectangle with rounded corners, hereinafter referred to as an oval. The optional argument portion allows you to produce only half or a quarter of the oval. For half an oval take portion to be one of these.
t
top half
b
bottom half
r
right half
l
left half
Produce only one quarter of the oval by setting portion to
tr
, br
, bl
, or tl
.
This draws the top half of an oval that is 3 wide and 7 tall.
\put(5,7){\oval(3,7)[t]}
The (5,7) is the center of the entire oval, not just the center of the top half.
These shapes are not ellipses. They are rectangles whose corners are
made with quarter circles. These circles have a maximum radius of
20pt (see \circle
for the sizes). Thus large ovals are just
frames with a small amount of corner rounding.
\shortstack
¶Synopsis:
\shortstack[position]{line 1 \\ ... }
Produce a vertical stack of objects.
This labels the y axis by writing the word ‘y’ above the word ‘axis’.
\setlength{\unitlength}{1cm} \begin{picture}(5,2.5)(-0.75,0) \put(0,0){\vector(1,0){4}} % x axis \put(0,0){\vector(0,1){2}} % y \put(-0.2,2){\makebox(0,0)[r]{\shortstack[r]{$y$\\ axis}}} \end{picture}
For a short stack, the reference point is the lower left of the stack.
In the above example the \makebox
(see \mbox
& \makebox
) puts
the stack flush right in a zero width box so in total the short stack
sits slightly to the left of the y axis.
The valid positions are:
r
Make objects flush right
l
Make objects flush left
c
Center objects (default)
Separate objects into lines with \\
. These stacks are short in
that, unlike in a tabular
or array
environment, here the
rows are not spaced out to be of even baseline skips. Thus, in
\shortstack{X\\o\\o\\X}
the first and last rows are taller than
the middle two, and therefore the baseline skip between the two middle
rows is smaller than that between the third and last row. You can
adjust row heights and depths either by putting in the usual interline
spacing with \shortstack{X\\ \strut o\\o\\X}
(see \strut
),
or explicitly, via an zero-width box \shortstack{X \\
\rule{0pt}{12pt} o\\o\\X}
or by using \\
’s optional
argument \shortstack{X\\[2pt] o\\o\\X}
.
The \shortstack
command is also available outside the
picture
environment.
\vector
¶Synopsis:
\vector(x_run,y_rise){travel}
Draw a line ending in an arrow. The slope of that line is: it vertically rises y_rise for every horizontal x_run. The travel is the total horizontal change—it is not the length of the vector, it is the change in x. In the special case of vertical vectors, if (x_run,y_rise)=(0,1), then travel gives the change in y.
For an example see picture
.
For elaboration on x_run and y_rise see \line
. As
there, the values of x_run and y_rise are limited. For
\vector
you must chooses integers between −4 and 4,
inclusive. Also, the two you choose must be relatively prime. Thus,
\vector(2,1){4}
is acceptable but \vector(4,2){4}
is
not (if you use the latter then you get a sequence of arrowheads).
\makebox
(picture) ¶Synopsis:
\makebox(rec-width,rec-height){text} \makebox(rec-width,rec-height)[position]{text}
Make a box to hold text. This command fits with the
picture
environment, although you can use it outside of there,
because rec-width and rec-height are numbers specifying
distances in terms of the \unitlength
(see picture
). This
command is similar to the normal \makebox
command (see \mbox
& \makebox
) except here that you must specify the width and height. This
command is fragile (see \protect
).
This makes a box of length 3.5 times \unitlength
and height 4
times \unitlength
.
\put(1,2){\makebox(3.5,4){...}}
The optional argument position
specifies where in the box
the text appears. The default is to center it, both horizontally
and vertically. To place it somewhere else, use a string with one or
two of these letters.
t
Puts text the top of the box.
b
Put text at the bottom.
l
Put text on the left.
r
Put text on the right.
\framebox
(picture) ¶Synopsis:
\framebox(rec-width,rec-height){text} \framebox(rec-width,rec-height)[position]{text}
This is the same as \makebox
(picture) except that it puts a frame
around the outside of the box that it creates. The reference point is
the bottom left corner of the frame. This command fits with the
picture
environment, although you can use it outside of there,
because lengths are numbers specifying the distance in terms of the
\unitlength
(see picture
). This command is fragile
(see \protect
).
This example creates a frame 2.5 inches by 3 inches and puts the text in the center.
\setlength{\unitlength}{1in} \framebox(2.5,3){test text}
The required arguments are that the rectangle has overall width rect-width units and height rect-height units.
The optional argument position specifies the position of
text; see \makebox
(picture) for the values that it can
take.
The rule has thickness \fboxrule
and there is a blank space
\fboxsep
between the frame and the contents of the box.
For this command, you must specify the width and height. If
you want to just put a frame around some contents whose dimension is
determined in some other way then either use \fbox
(see \fbox
& \framebox
) or \frame
(see \frame
).
\frame
¶Synopsis:
\frame{contents}
Puts a rectangular frame around contents. The reference point
is the bottom left corner of the frame. In contrast to
\framebox
(see \framebox
(picture)), this command puts no
extra space between the frame and the object. It is fragile
(see \protect
).
\dashbox
¶Synopsis:
\dashbox{dash-len}(rect-width,rect-height){text} \dashbox{dash-len}(rect-width,rect-height)[position]{text}
Create a dashed rectangle around text. This command fits with the
picture
environment, although you can use it outside of there,
because lengths are numbers specifying the distance in terms of the
\unitlength
(see picture
).
The required arguments are: dashes are dash-len units long, with the same length gap, and the rectangle has overall width rect-width units and height rect-height units.
The optional argument position specifies the position of
text; see \makebox
(picture) for the values that it can
take.
This shows that you can use non-integer value for dash-len.
\put(0,0){\dashbox{0.1}(5,0.5){My hovercraft is full of eels.}}
Each dash will be 0.1\unitlength
long, the box’s width is
5\unitlength
and its height is 0.5\unitlength
.
As in that example, a dashed box looks best when rect-width and rect-height are multiples of the dash-len.
quotation
& quote
¶Synopsis:
\begin{quotation} text \end{quotation}
or
\begin{quote} text \end{quote}
Include a quotation. Both environments indent margins on both sides by
\leftmargin
and the text is right-justified.
They differ in how they treat paragraphs. In the quotation
environment, paragraphs are indented by 1.5em and the space
between paragraphs is small, 0pt plus 1pt
. In the quote
environment, paragraphs are not indented and there is vertical space
between paragraphs (it is the rubber length \parsep
).
\begin{quotation} \small\it Four score and seven years ago ... shall not perish from the earth. \hspace{1em plus 1fill}---Abraham Lincoln \end{quotation}
tabbing
¶Synopsis:
\begin{tabbing} row1col1 \= row1col2 ... \\ row2col1 \> row2col2 ... \\ ... \end{tabbing}
Align text in columns, by setting tab stops and tabbing to them much as
was done on a typewriter. This is less often used than the environments
tabular
(see tabular
) or array
(see array
) because
in those the width of each column need not be constant and need not be
known in advance.
This example has a first line where the tab stops are set to explicit
widths, ended by a \kill
command (which is described below):
\begin{tabbing} \hspace{1.2in}\=\hspace{1in}\=\kill Ship \>Guns \>Year \\ \textit{Sophie} \>14 \>1800 \\ \textit{Polychrest} \>24 \>1803 \\ \textit{Lively} \>38 \>1804 \\ \textit{Surprise} \>28 \>1805 \\ \end{tabbing}
Both the tabbing
environment and the more widely-used
tabular
environment put text in columns. The most important
distinction is that in tabular
the width of columns is
determined automatically by LaTeX, while in tabbing
the user
sets the tab stops. Another distinction is that tabular
generates a box, but tabbing
can be broken across pages.
Finally, while tabular
can be used in any mode, tabbing
can be used only in paragraph mode and it always starts a new paragraph,
without indentation.
Moreover, as shown in the example above, there is no need
to use the starred form of the \hspace
command at the beginning
of a tabbed row. The right margin of the tabbing
environment is
the end of line, so that the width of the environment is
\linewidth
.
The tabbing
environment contains a sequence of tabbed
rows. The first tabbed row begins immediately after
\begin{tabbing}
and each row ends with \\
or
\kill
. The last row may omit the \\
and end with just
\end{tabbing}
.
At any point the tabbing
environment has a current tab stop
pattern, a sequence of n > 0 tab stops, numbered 0, 1,
etc. These create n corresponding columns. Tab stop 0 is
always the left margin, defined by the enclosing environment. Tab
stop number i is set if it is assigned a horizontal
position on the page. Tab stop number i can only be set if
all the stops 0, …, i-1 have already been set; normally
later stops are to the right of earlier ones.
By default any text typeset in a tabbing
environment is typeset
ragged right and left-aligned on the current tab stop. Typesetting is
done in LR mode (see Modes).
The following commands can be used inside a tabbing
environment.
They are all fragile (see \protect
).
\\ (tabbing)
¶End a tabbed line and typeset it.
\= (tabbing)
¶Sets a tab stop at the current position.
\> (tabbing)
¶Advances to the next tab stop.
\<
¶Put following text to the left of the local margin (without changing the margin). Can only be used at the start of the line.
\+
¶Moves the left margin of the next and all the following commands one tab stop to the right, beginning tabbed line if necessary.
\-
¶Moves the left margin of the next and all the following commands one tab stop to the left, beginning tabbed line if necessary.
\' (tabbing)
¶Moves everything that you have typed so far in the current column, i.e.,
everything from the most recent \>
, \<
, \'
,
\\
, or \kill
command, to the previous column and aligned
to the right, flush against the current column’s tab stop.
\` (tabbing)
¶Allows you to put text flush right against any tab stop, including tab
stop 0. However, it can’t move text to the right of the last
column because there’s no tab stop there. The \`
command moves
all the text that follows it, up to the \\
or
\end{tabbing}
command that ends the line, to the right margin
of the tabbing
environment. There must be no \>
or
\'
command between the \`
and the \\
or
\end{tabbing}
command that ends the line.
\a (tabbing)
¶In a tabbing
environment, the commands \=
, \'
and
\`
do not produce accents as usual (see Accents). Instead,
use the commands \a=
, \a'
and \a`
.
\kill
¶Sets tab stops without producing text. Works just like \\
except
that it throws away the current line instead of producing output for it.
Any \=
, \+
or \-
commands in that line remain in
effect.
\poptabs
¶Restores the tab stop positions saved by the last \pushtabs
.
\pushtabs
¶Saves all current tab stop positions. Useful for temporarily changing
tab stop positions in the middle of a tabbing
environment.
\tabbingsep
¶Distance of the text moved by \'
to left of current tab stop.
This example typesets a Pascal function:
\begin{tabbing} function \= fact(n : integer) : integer;\\ \> begin \= \+ \\ \> if \= n > 1 then \+ \\ fact := n * fact(n-1) \- \\ else \+ \\ fact := 1; \-\- \\ end;\\ \end{tabbing}
The output looks like this.
function fact(n : integer) : integer; begin if n > 1 then fact := n * fact(n-1); else fact := 1; end;
This example is just for illustration of the environment. To actually
typeset computer code in typewriter like this, a verbatim environment
(see verbatim
) would normally be best. For pretty-printed code,
there are quite a few packages, including algorithm2e
,
fancyvrb
, listings
, and minted
.
table
¶Synopsis:
\begin{table}[placement] table body \caption[loftitle]{title} % optional \label{label} % also optional \end{table}
A class of floats (see Floats). They cannot be split across pages and so they are not typeset in sequence with the normal text but instead are floated to a convenient place, such as the top of a following page.
This example table
environment contains a tabular
\begin{table} \centering\small \begin{tabular}{ll} \multicolumn{1}{c}{\textit{Author}} &\multicolumn{1}{c}{\textit{Piece}} \\ \hline Bach &Cello Suite Number 1 \\ Beethoven &Cello Sonata Number 3 \\ Brahms &Cello Sonata Number 1 \end{tabular} \caption{Top cello pieces} \label{tab:cello} \end{table}
but you can put many different kinds of content in a table
:
the table body may contain text, LaTeX commands, graphics, etc. It is
typeset in a parbox
of width \textwidth
.
For the possible values of placement and their effect on the float placement algorithm, see Floats.
The label is optional; it is used for cross references (see Cross references).
The \caption
command is also optional. It specifies caption
text title for the table (see \caption
). By default it is
numbered. If its optional lottitle is present then that text is
used in the list of tables instead of title (see Table of contents, list of figures, list of tables).
In this example the table and caption will float to the bottom of a page, unless it is pushed to a float page at the end.
\begin{table}[b] \centering \begin{tabular}{r|p{2in}} \hline One &The loneliest number \\ Two &Can be as sad as one. It's the loneliest number since the number one. \end{tabular} \caption{Cardinal virtues} \label{tab:CardinalVirtues} \end{table}
tabular
¶Synopsis:
\begin{tabular}[pos]{cols} column 1 entry &column 2 entry ... &column n entry \\ ... \end{tabular}
or
\begin{tabular*}{width}[pos]{cols} column 1 entry &column 2 entry ... &column n entry \\ ... \end{tabular*}
Produce a table, a box consisting of a sequence of horizontal rows. Each row consists of items that are aligned vertically in columns. This illustrates many of the features.
\begin{tabular}{l|l} \textit{Player name} &\textit{Career home runs} \\ \hline Hank Aaron &755 \\ Babe Ruth &714 \end{tabular}
The output will have two left-aligned columns with a vertical bar
between them. This is specified in tabular
’s argument
{l|l}
.
Put the entries into different columns by separating them with an
ampersand, &
. The end of each row is marked with a double
backslash, \\
. Put a horizontal rule below a row, after a double
backslash, with \hline
.
After the last row the \\
is optional, unless an \hline
command follows to put a rule below the table.
The required and optional arguments to tabular
consist of:
Optional. Specifies the table’s vertical position. The default is to
align the table so its vertical center matches the baseline of the
surrounding text. There are two other possible alignments: t
aligns the table so its top row matches the baseline of the surrounding
text, and b
aligns on the bottom row.
This only has an effect if there is other text. In the common case of a
tabular
alone in a center
environment this option makes
no difference.
Required. Specifies the formatting of columns. It consists of a sequence of the following specifiers, corresponding to the types of column and intercolumn material.
l
A column of left-aligned items.
r
A column of right-aligned items.
c
A column of centered items.
|
A vertical line the full height and depth of the environment.
@{text or space}
Insert text or space at this location in every row. The text
or space material is typeset in LR mode. This text is fragile
(see \protect
).
If between two column specifiers there is no @-expression then
LaTeX’s book
, article
, and report
classes will
put on either side of each column a space of width \tabcolsep
,
which by default is 6pt. That is, by default adjacent columns are
separated by 12pt (so \tabcolsep
is misleadingly named
since it is only half of the separation between tabular columns). In
addition, a space of \tabcolsep
also comes before the first
column and after the final column, unless you put a @{...}
there.
If you override the default and use an @-expression then LaTeX does
not insert \tabcolsep
so you must insert any desired space
yourself, as in @{\hspace{1em}}
.
An empty expression @{}
will eliminate the space. In
particular, sometimes you want to eliminate the space before the first
column or after the last one, as in the example below where the
tabular lines need to lie on the left margin.
\begin{flushleft} \begin{tabular}{@{}l} ... \end{tabular} \end{flushleft}
The next example shows text, a decimal point between the columns, arranged so the numbers in the table are aligned on it.
\begin{tabular}{r@{$.$}l} $3$ &$14$ \\ $9$ &$80665$ \end{tabular}
An \extracolsep{wd}
command in an @-expression causes an
extra space of width wd to appear to the left of all subsequent
columns, until countermanded by another \extracolsep
. Unlike
ordinary intercolumn space, this extra space is not suppressed by an
@-expression. An \extracolsep
command can be used only in an
@-expression in the cols
argument. Below, LaTeX inserts the
right amount of intercolumn space to make the entire table 4 inches
wide.
\begin{tabular*}{4in}{l@{\extracolsep{\fill}}l} Seven times down, eight times up \ldots &such is life! \end{tabular*}
To insert commands that are automatically executed before a given
column, load the array
package and use the >{...}
specifier.
p{wd}
Each item in the column is typeset in a parbox of width wd, as if
it were the argument of a \parbox[t]{wd}{...}
command.
A line break double backslash \\
may not appear in the item,
except inside an environment like minipage
, array
, or
tabular
, or inside an explicit \parbox
, or in the scope of
a \centering
, \raggedright
, or \raggedleft
declaration (when used in a p
-column element these declarations
must appear inside braces, as with {\centering .. \\
..}
). Otherwise LaTeX will misinterpret the double backslash as
ending the tabular row. Instead, to get a line break in there use
\newline
(see \newline
).
*{num}{cols}
Equivalent to num copies of cols, where num is a
positive integer and cols is a list of specifiers. Thus the
specifier \begin{tabular}{|*{3}{l|r}|}
is equivalent to
the specifier \begin{tabular}{|l|rl|rl|r|}
. Note that
cols may contain another *
-expression.
Required for tabular*
, not allowed for tabular
. Specifies
the width of the tabular*
environment. The space between columns
should be rubber, as with @{\extracolsep{\fill}}
, to allow
the table to stretch or shrink to make the specified width, or else you
are likely to get the Underfull \hbox (badness 10000) in alignment
...
warning.
Parameters that control formatting:
\arrayrulewidth
¶A length that is the thickness of the rule created by |
,
\hline
, and \vline
in the tabular
and array
environments. The default is ‘.4pt’. Change it as in
\setlength{\arrayrulewidth}{0.8pt}
.
\arraystretch
¶A factor by which the spacing between rows in the tabular
and
array
environments is multiplied. The default is ‘1’, for
no scaling. Change it as \renewcommand{\arraystretch}{1.2}
.
\doublerulesep
¶A length that is the distance between the vertical rules produced by the
||
specifier. The default is ‘2pt’.
\tabcolsep
¶A length that is half of the space between columns. The default is
‘6pt’. Change it with \setlength
.
The following commands can be used inside the body of a tabular
environment, the first two inside an entry and the second two between
lines:
\multicolumn
¶Synopsis:
\multicolumn{numcols}{cols}{text}
Make an array
or tabular
entry that spans several columns.
The first argument numcols gives the number of columns to span.
The second argument cols specifies the formatting of the entry,
with c
for centered, l
for flush left, or r
for
flush right. The third argument text gives the contents of that
entry.
In this example, in the first row, the second and third columns are spanned by the single heading ‘Name’.
\begin{tabular}{lccl} \textit{ID} &\multicolumn{2}{c}{\textit{Name}} &\textit{Age} \\ \hline 978-0-393-03701-2 &O'Brian &Patrick &55 \\ ... \end{tabular}
What counts as a column is: the column format specifier for the
array
or tabular
environment is broken into parts, where
each part (except the first) begins with l
, c
, r
,
or p
. So from \begin{tabular}{|r|ccp{1.5in}|}
the parts are |r|
, c
, c
,
and p{1.5in}|
.
The cols argument overrides the array
or tabular
environment’s intercolumn area default adjoining this multicolumn
entry. To affect that area, this argument can contain vertical bars
|
indicating the placement of vertical rules, and @{...}
expressions. Thus if cols is ‘|c|’ then this multicolumn
entry will be centered and a vertical rule will come in the intercolumn
area before it and after it. This table details the exact behavior.
\begin{tabular}{|cc|c|c|} \multicolumn{1}{r}{w} % entry one &\multicolumn{1}{|r|}{x} % entry two &\multicolumn{1}{|r}{y} % entry three &z % entry four \end{tabular}
Before the first entry the output will not have a vertical rule because
the \multicolumn
has the cols specifier ‘r’ with no
initial vertical bar. Between entry one and entry two there will be a
vertical rule; although the first cols does not have an ending
vertical bar, the second cols does have a starting one. Between
entry two and entry three there is a single vertical rule; despite that
the cols in both of the surrounding multicolumn
’s call for
a vertical rule, you only get one rule. Between entry three and entry
four there is no vertical rule; the default calls for one but the
cols in the entry three \multicolumn
leaves it out, and
that takes precedence. Finally, following entry four there is a
vertical rule because of the default.
The number of spanned columns numcols can be 1. Besides giving
the ability to change the horizontal alignment, this also is useful to
override for one row the tabular
definition’s default intercolumn
area specification, including the placement of vertical rules.
In the example below, in the tabular
definition the first column
is specified to default to left justified but in the first row the entry
is centered with \multicolumn{1}{c}{\textsc{Period}}
.
Also in the first row, the second and third columns are spanned by a
single entry with \multicolumn{2}{c}{\textsc{Span}}
,
overriding the specification to center those two columns on the page
range en-dash.
\begin{tabular}{l|r@{--}l} \multicolumn{1}{c}{\textsc{Period}} &\multicolumn{2}{c}{\textsc{Span}} \\ \hline Baroque &1600 &1760 \\ Classical &1730 &1820 \\ Romantic &1780 &1910 \\ Impressionistic &1875 &1925 \end{tabular}
Although the tabular
specification by default puts a vertical
rule between the first and second columns, no such vertical rule appears
in the first row here. That’s because there is no vertical bar in the
cols part of the first row’s first \multicolumn
command.
\vline
¶Draw a vertical line in a tabular
or array
environment
extending the full height and depth of an entry’s row. Can also be
used in an @-expression, although its synonym vertical
bar |
is more common. This command is rarely used in the
body of a table; typically a table’s vertical lines are specified in
tabular
’s cols argument and overridden as needed with
\multicolumn
(see tabular
).
The example below illustrates some pitfalls. In the first row’s second
entry the \hfill
moves the \vline
to the left edge of the
cell. But that is different than putting it halfway between the two
columns, so between the first and second columns there are two vertical
rules, with the one from the {c|cc}
specifier coming before the
one produced by the \vline\hfill
. In contrast, the first row’s
third entry shows the usual way to put a vertical bar between two
columns. In the second row, the ghi
is the widest entry in its
column so in the \vline\hfill
the \hfill
has no effect and
the vertical line in that entry appears immediately next to the
g
, with no whitespace.
\begin{tabular}{c|cc} x &\vline\hfill y &\multicolumn{1}{|r}{z} \\ % row 1 abc &def &\vline\hfill ghi % row 2 \end{tabular}
\cline
¶Synopsis:
\cline{i-j}
In an array
or tabular
environment, draw a horizontal rule
beginning in column i and ending in column j. The
dash, -
, must appear in the mandatory argument. To span a single
column use the number twice, as with \cline{2-2}
.
This example puts two horizontal lines between the first and second rows, one line in the first column only, and the other spanning the third and fourth columns. The two lines are side-by-side, at the same height.
\begin{tabular}{llrr} a &b &c &d \\ \cline{1-1} \cline{3-4} e &f &g &h \end{tabular}
\hline
¶Draw a horizontal line the width of the enclosing tabular
or
array
environment. It’s most commonly used to draw a line at the
top, bottom, and between the rows of a table.
In this example the top of the table has two horizontal rules, one above
the other, that span both columns. The bottom of the table has a single
rule spanning both columns. Because of the \hline
, the
tabular
second row’s line ending double backslash \\
is required.
\begin{tabular}{ll} \hline\hline Baseball &Red Sox \\ Basketball &Celtics \\ \hline \end{tabular}
thebibliography
¶Synopsis:
\begin{thebibliography}{widest-label} \bibitem[label]{cite_key} ... \end{thebibliography}
Produce a bibliography or reference list. There are two ways to produce bibliographic lists. This environment is suitable when you have only a few references and can maintain the list by hand. See Using BibTeX, for a more sophisticated approach.
This shows the environment with two entries.
This work is based on \cite{latexdps}. Together they are \cite{latexdps, texbook}. ... \begin{thebibliography}{9} \bibitem{latexdps} Leslie Lamport. \textit{\LaTeX{}: a document preparation system}. Addison-Wesley, Reading, Massachusetts, 1993. \bibitem{texbook} Donald Ervin Knuth. \textit{The \TeX book}. Addison-Wesley, Reading, Massachusetts, 1983. \end{thebibliography}
This styles the first reference as ‘[1] Leslie ...’, and so that
... based on \cite{latexdps}
produces the matching
‘... based on [1]’. The second \cite
produces ‘[1,
2]’. You must compile the document twice to resolve these references.
The mandatory argument widest-label is text that, when typeset, is
as wide as the widest item label produced by the \bibitem
commands. The tradition is to use 9
for bibliographies with less
than 10 references, 99
for ones with less than 100, etc.
The bibliographic list is headed by a title such as ‘Bibliography’.
To change it there are two cases. In the book and report
classes, where the top level sectioning is \chapter
and the
default title is ‘Bibliography’, that title is in the macro
\bibname
. For article, where the class’s top level
sectioning is \section
and the default is ‘References’, the
title is in macro \refname
. Change it by redefining the command,
as with \renewcommand{\refname}{Cited references}
, after
\begin{document}
.
Language support packages such as babel
will automatically
redefine \refname
or \bibname
to fit the selected
language.
See list
, for the list layout control parameters.
\bibitem
¶Synopsis:
\bibitem{cite_key}
or
\bibitem[label]{cite_key}
Generate an entry labeled by default by a number generated using the
enumi
counter. The citation key
cite_key can be any string of
letters, numbers, and punctuation symbols (but not comma).
See thebibliography
, for an example.
When provided, the optional label becomes the entry label and the
enumi
counter is not incremented. With this
\begin{thebibliography} \bibitem[Lamport 1993]{latexdps} Leslie Lamport. \textit{\LaTeX{}: a document preparation system}. Addison-Wesley, Reading, Massachusetts, 1993. \bibitem{texbook} Donald Ervin Knuth. \textit{The \TeX book}. Addison-Wesley, Reading, Massachusetts, 1983. \end{thebibliography}
the first entry will be styled as ‘[Lamport 1993] Leslie ...’ (The
amount of horizontal space that LaTeX leaves for the label depends on
the widest-label argument of the thebibliography
environment; see thebibliography
.) Similarly, ... based on
\cite{latexdps}
will produce ‘... based on [Lamport 1994]’.
If you mix \bibitem
entries having a label with those that
do not then LaTeX will number the unlabelled ones sequentially. In
the example above the texbook
entry will appear as ‘[1]
Donald ...’, despite that it is the second entry.
If you use the same cite_key twice then you get ‘LaTeX Warning: There were multiply-defined labels’.
Under the hood, LaTeX remembers the cite_key and label
information because \bibitem
writes it to the auxiliary file
jobname.aux (see Jobname). For instance, the above
example causes the two \bibcite{latexdps}{Lamport, 1993}
and
\bibcite{texbook}{1}
to appear in that file. The .aux
file is read by the \begin{document}
command and then the
information is available for \cite
commands. This explains why
you need to run LaTeX twice to resolve references: once to write it
out and once to read it in.
Because of this two-pass algorithm, when you add a \bibitem
or
change its cite_key you may get ‘LaTeX Warning: Label(s) may
have changed. Rerun to get cross-references right’. Fix it by
recompiling.
\cite
¶Synopsis:
\cite{keys}
or
\cite[subcite]{keys}
Generate as output a citation to the references associated with
keys. The mandatory keys is a citation key, or a
comma-separated list of citation keys (see \bibitem
).
This
The ultimate source is \cite{texbook}. ... \begin{thebibliography} \bibitem{texbook} Donald Ervin Knuth. \textit{The \TeX book}. Addison-Wesley, Reading, Massachusetts, 1983. \end{thebibliography}
produces output like ‘... source is [1]’. You can change the
appearance of the citation and of the reference by using bibliography
styles if you generate automatically the thebibliography
environment. More information in Using BibTeX.
The optional argument subcite is appended to the citation. For
example, See 14.3 in \cite[p.~314]{texbook}
might produce
‘See 14.3 in [1, p. 314]’.
In addition to what appears in the output, \cite
writes
information to the auxiliary file jobname.aux
(see Jobname). For instance, \cite{latexdps}
writes
‘\citation{latexdps}’ to that file. This information is used by
BibTeX to include in your reference list only those works that you
have actually cited; see \nocite
also.
If keys is not in your bibliography information then you get
‘LaTeX Warning: There were undefined references’, and in the output
the citation shows as a boldface question mark between square brackets.
There are two possible causes. If you have mistyped something, as in
\cite{texbok}
then you need to correct the spelling. On the
other hand, if you have just added or modified the bibliographic
information and so changed the .aux file (see \bibitem
) then
the fix may be to run LaTeX again.
\nocite
¶Synopsis:
\nocite{keys}
Produces no output but writes keys to the auxiliary file jobname.aux (see Jobname).
The mandatory argument keys is a comma-separated list of one or
more citation keys (see \bibitem
). This information is used by
BibTeX to include these works in your reference list even though you
have not explicitly cited them (see \cite
).
As described in thebibliography
(see thebibliography
), a
sophisticated approach to managing bibliographies is provided by the
BibTeX program. This is only an introduction; see the full
documentation on CTAN (see CTAN: The Comprehensive TeX Archive Network).
With BibTeX, you don’t use the thebibliography
environment
directly (see thebibliography
). Instead, include these lines:
\bibliographystyle{bibstyle} \bibliography{bibfile1, bibfile2, ...}
The bibstyle refers to a file bibstyle.bst, which defines how your citations will look. The standard bibstyle’s distributed with BibTeX are:
alpha
Labels are formed from name of author and year of publication. The bibliographic items are sorted alphabetically.
plain
Labels are integers. Sort the bibliographic items alphabetically.
unsrt
Like plain
, but entries are in order of citation.
abbrv
Like plain
, but more compact labels.
Many, many other BibTeX style files exist, tailored to the demands of various publications. See the CTAN topic https://ctan.org/topic/bibtex-sty.
The \bibliography
command is what actually produces the
bibliography. Its argument is a comma-separated list, referring to
files named bibfile1.bib, bibfile2.bib,
… These contain your database in BibTeX format. This shows a
typical couple of entries in that format.
@book{texbook, title = {The {{\TeX}}book}, author = {D.E. Knuth}, isbn = {0201134489}, series = {Computers \& typesetting}, year = {1983}, publisher = {Addison-Wesley} } @book{sexbook, author = {W.H. Masters and V.E. Johnson}, title = {Human Sexual Response}, year = {1966}, publisher = {Bantam Books} }
Only the bibliographic entries referred to via \cite
and
\nocite
will be listed in the document’s bibliography. Thus you
can keep all your sources together in one file, or a small number of
files, and rely on BibTeX to include in this document only those that
you used.
With BibTeX, the keys argument to \nocite
can also be
the single character ‘*’. This means to implicitly cite all
entries from all given bibliographies.
If you forget to use \bibliography
or \bibliographystyle
in your document (or, less likely, any \cite
or \nocite
command), BibTeX will issue an error message. Because BibTeX
can be used with any program, not just LaTeX, the error messages
refer to the internal commands read by BibTeX (from the .aux
file), rather than the user-level commands described above.
Here is a table showing internal commands mentioned in the BibTeX errors, and the corresponding user-level commands.
For example, if your document has no \bibliographystyle
command, BibTeX complains as follows:
I found no \bibstyle command---while reading file document.aux
theorem
¶Synopsis:
\begin{theorem} theorem body \end{theorem}
Produces ‘Theorem n’ in boldface followed by theorem
body in italics. The numbering possibilities for n are described under
\newtheorem
(see \newtheorem
).
\newtheorem{lem}{Lemma} % in preamble \newtheorem{thm}{Theorem} ... \begin{lem} % in document body text of lemma \end{lem} The next result follows immediately. \begin{thm}[Gauss] % put `Gauss' in parens after theorem head text of theorem \end{thm}
Most new documents use the packages amsthm
and amsmath
from the American Mathematical Society. Among other things these
packages include a large number of options for theorem environments,
such as styling options.
titlepage
¶Synopsis:
\begin{titlepage} ... text and spacing ... \end{titlepage}
Create a title page, a page with no printed page number or heading and with succeeding pages numbered starting with page one.
In this example all formatting, including vertical spacing, is left to the author.
\begin{titlepage} \vspace*{\stretch{1}} \begin{center} {\huge\bfseries Thesis \\[1ex] title} \\[6.5ex] {\large\bfseries Author name} \\ \vspace{4ex} Thesis submitted to \\[5pt] \textit{University name} \\[2cm] in partial fulfilment for the award of the degree of \\[2cm] \textsc{\Large Doctor of Philosophy} \\[2ex] \textsc{\large Mathematics} \\[12ex] \vfill Department of Mathematics \\ Address \\ \vfill \today \end{center} \vspace{\stretch{2}} \end{titlepage}
To instead produce a standard title page without a titlepage
environment, use \maketitle
(see \maketitle
).
verbatim
¶Synopsis:
\begin{verbatim} literal-text \end{verbatim}
A paragraph-making environment in which LaTeX produces as output
exactly what you type as input. For instance inside literal-text
the backslash \
character does not start commands, it
produces a printed ‘\’, and carriage returns and blanks are taken
literally. The output appears in a monospaced typewriter-like font
(\tt
).
\begin{verbatim} Symbol swearing: %&$#?!. \end{verbatim}
The only restriction on literal-text
is that it cannot include
the string \end{verbatim}
.
You cannot use the verbatim environment in the argument to macros, for
instance in the argument to a \section
. This is not the same as
commands being fragile (see \protect
), instead it just cannot work,
as the verbatim
environment changes the catcode regime before
processing its contents, and restore it immediately afterward,
nevertheless with a macro argument the content of the argument has
already be converted to a token list along the catcode regime in effect
when the macro was called. However, the cprotect
package can
help with this.
One common use of verbatim input is to typeset computer code. Some
packages offer many features not provided by the verbatim
environment; two of the most popular are listings
and
minted
. For example, they are capable of pretty-printing,
line numbering, and selecting parts of files for a continuing listing.
A package that provides many more options for verbatim environments is
fancyvrb
. Another is verbatimbox
.
For a list of all the relevant packages, see CTAN (see CTAN: The Comprehensive TeX Archive Network),
particularly the topics listing
(https://ctan.org/topic/listing) and verbatim
(https://ctan.org/topic/verbatim).
\verb
¶Synopsis:
\verb char literal-text char \verb* char literal-text char
Typeset literal-text as it is input, including special characters
and spaces, using the typewriter (\tt
) font.
This example shows two different invocations of \verb
.
This is \verb!literally! the biggest pumpkin ever. And this is the best squash, \verb+literally!+
The first \verb
has its literal-text surrounded with
exclamation point, !
. The second instead uses plus, +
,
because the exclamation point is part of literal-text
.
The single-character delimiter char surrounds
literal-text—it must be the same character before and after.
No spaces come between \verb
or \verb*
and char,
or between char and literal-text, or between
literal-text and the second occurrence of char (the
synopsis shows a space only to distinguish one component from the
other). The delimiter must not appear in literal-text. The
literal-text cannot include a line break.
The *
-form differs only in that spaces are printed with a visible
space character.
The output from this will include a visible space on both side of word ‘with’:
The command's first argument is \verb*!filename with extension! and ...
For typesetting Internet addresses, urls, the package url
is a better option than the \verb
command, since
it allows line breaks.
You cannot use \verb
in the argument to a macro, for instance in
the argument to a \section
. It is not a question of \verb
being fragile (see \protect
), instead it just cannot work, as the
\verb
command changes the catcode regime before reading its
argument, and restore it immediately afterward, nevertheless with a
macro argument the content of the argument has already be converted to a
token list along the catcode regime in effect when the macro was called.
However, the cprotect
package can help with this.
verse
¶Synopsis:
\begin{verse} line1 \\ line2 \\ ... \end{verse}
An environment for poetry.
Here are two lines from Shakespeare’s Romeo and Juliet.
Then plainly know my heart's dear love is set \\ On the fair daughter of rich Capulet.
Separate the lines of each stanza with \\
, and use one or more
blank lines to separate the stanzas.
\begin{verse} \makebox[\linewidth][c]{\textit{Shut Not Your Doors} ---Walt Whitman} \\[1\baselineskip] Shut not your doors to me proud libraries, \\ For that which was lacking on all your well-fill'd shelves, \\ \qquad yet needed most, I bring, \\ Forth from the war emerging, a book I have made, \\ The words of my book nothing, the drift of it every thing, \\ A book separate, not link'd with the rest nor felt by the intellect, \\ But you ye untold latencies will thrill to every page. \end{verse}
The output has margins indented on the left and the right, paragraphs are not indented, and the text is not right-justified.
The first thing LaTeX does when processing ordinary text is to translate your input file into a sequence of glyphs and spaces. To produce a printed document, this sequence must be broken into lines (and these lines must be broken into pages).
LaTeX usually does the line (and page) breaking in the text body for you but in some environments you manually force line breaks.
A common workflow is to get a final version of the document content before taking a final pass through and considering line breaks (and page breaks). This differs from word processing, where you are formatting text as you input it. Putting these off until the end prevents a lot of fiddling with breaks that will change anyway.
\\
\obeycr
& \restorecr
\newline
\-
(discretionary hyphen)\slash
: breakable ‘/’\discretionary
(generalized hyphenation point)\fussy
& \sloppy
\hyphenation
\linebreak
& \nolinebreak
\\
¶Synopsis, one of:
\\ \\[morespace]
or one of:
\\* \\*[morespace]
End the current line. The optional argument morespace specifies
extra vertical space to be inserted before the next line. This is a
rubber length (see Lengths) and can be negative. The text before
the line break is set at its normal length, that is, it is not stretched
to fill out the line width. This command is fragile (see \protect
).
\title{My story: \\[0.25in] a tale of woe}
The starred form, \\*
, tells LaTeX not to start a new page
between the two lines, by issuing a \nobreak
.
Explicit line breaks in the main text body are unusual in LaTeX. In
particular, don’t start new paragraphs with \\
. Instead leave a
blank line between the two paragraphs. And don’t put in a sequence of
\\
’s to make vertical space. Instead use
\vspace{length}
, or
\leavevmode\vspace{length}
, or
\vspace*{length}
if you want the space to not be thrown
out at the top of a new page (see \vspace
).
The \\
command is mostly used outside of the main flow of text
such as in a tabular
or array
environment or in an
equation environment.
The \\
command is a synonym for \newline
(see \newline
) under ordinary circumstances (an example of an
exception is the p{...}
column in a tabular
environment; see tabular
).
The \\
command is a macro, and its definition changes by context
so that its definition in normal text, a center
environment, a
flushleft
environment, and a tabular
are all different.
In normal text when it forces a linebreak it is essentially a shorthand
for \newline
. It does not end horizontal mode or end the
paragraph, it just inserts some glue and penalties so that when the
paragraph does end a linebreak will occur at that point, with the short
line padded with white space.
You get ‘LaTeX Error: There's no line here to end’ if you use
\\
to ask for a new line, rather than to end the current line.
An example is if you have \begin{document}\\
or, more likely,
something like this.
\begin{center} \begin{minipage}{0.5\textwidth} \\ In that vertical space put your mark. \end{minipage} \end{center}
Fix it by replacing the double backslash with something like
\vspace{\baselineskip}
.
\obeycr
& \restorecr
¶The \obeycr
command makes a return in the input file (‘^^M’,
internally) the same as \\
, followed by \relax
. So each
new line in the input will also be a new line in the output. The
\restorecr
command restores normal line-breaking behavior.
This is not the way to show verbatim text or computer code. Use
verbatim
(see verbatim
) instead.
With LaTeX’s usual defaults, this
aaa bbb \obeycr ccc ddd eee \restorecr fff ggg hhh iii
produces output like this.
aaa bbb ccc ddd eee fff ggg hhh iii
The indents are paragraph indents.
\newline
¶In ordinary text, this ends a line in a way that does not right-justify
it, so the text before the end of line is not stretched. That is, in
paragraph mode (see Modes), the \newline
command is
equivalent to double-backslash (see \\
). This command is fragile
(see \protect
).
However, the two commands are different inside a tabular
or
array
environment. In a column with a specifier producing a
paragraph box such as typically p{...}
, \newline
will
insert a line end inside of the column; that is, it does not break the
entire tabular row. To break the entire row use \\
or its
equivalent \tabularnewline
.
This will print ‘Name:’ and ‘Address:’ as two lines in a single cell of the table.
\begin{tabular}{p{1in}@{\hspace{2in}}p{1in}} Name: \newline Address: &Date: \\ \hline \end{tabular}
The ‘Date:’ will be baseline-aligned with ‘Name:’.
\-
(discretionary hyphen) ¶Tell LaTeX that it may hyphenate the word at that point. When you
insert \-
commands in a word, the word will only be hyphenated at
those points and not at any of the other hyphenation points that
LaTeX might otherwise have chosen. This command is robust
(see \protect
).
LaTeX is good at hyphenating and usually finds most of the correct
hyphenation points, while almost never using an incorrect one. The
\-
command is for exceptional cases.
For example, LaTeX does not ordinarily hyphenate words containing a hyphen. Below, the long and hyphenated word means LaTeX has to put in unacceptably large spaces to set the narrow column.
\begin{tabular}{rp{1.75in}} Isaac Asimov &The strain of anti-intellectualism % an\-ti-in\-tel\-lec\-tu\-al\-ism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that `my ignorance is just as good as your knowledge'. \end{tabular}
Commenting out the third line and uncommenting the fourth makes a much better fit.
The \-
command only allows LaTeX to break there, it does not
require that it break there. You can force a split with something
like Hef-\linebreak feron
. Of course, if you later change the
text then this forced break may look out of place, so this approach
requires care.
\slash
: breakable ‘/’ ¶The \slash
command produces a ‘/’ character and then a
penalty of the same value as an explicit ‘-’ character
(\exhyphenpenalty
). This allows TeX to break a line at the
‘/’, similar to a hyphen. Hyphenation is allowed in the word part
preceding the ‘/’, but not after. For example:
The input\slash output of the program is complicated.
\discretionary
(generalized hyphenation point) ¶Synopsis:
\discretionary{pre-break}{post-break}{no-break}
Handle word changes around hyphens. This command is not often used in LaTeX documents.
If a line break occurs at the point where \discretionary
appears
then TeX puts pre-break at the end of the current line and puts
post-break at the start of the next line. If there is no line
break here then TeX puts no-break.
In ‘difficult’ the three letters ffi
form a ligature. But
TeX can nonetheless break between the two ‘f’’s with this.
di\discretionary{f-}{fi}{ffi}cult
Note that users do not have to do this. It is typically handled automatically by TeX’s hyphenation algorithm.
\fussy
& \sloppy
¶Declarations to make TeX more picky or less picky about line
breaking. Declaring \fussy
usually avoids too much space between
words, at the cost of an occasional overfull box. Conversely,
\sloppy
avoids overfull boxes while suffering loose interword
spacing.
The default is \fussy
. Line breaking in a paragraph is
controlled by whichever declaration is current at the end of the
paragraph, i.e., at the blank line or \par
or displayed
equation ending that paragraph. So to affect the line breaks, include
that paragraph-ending material in the scope of the command.
sloppypar
¶Synopsis:
\begin{sloppypar} ... paragraphs ... \end{sloppypar}
Typeset the paragraphs with \sloppy
in effect (see \fussy
& \sloppy
). Use this to locally adjust line breaking, to avoid
‘Overfull box’ or ‘Underfull box’ errors.
The example is simple.
\begin{sloppypar} Her plan for the morning thus settled, she sat quietly down to her book after breakfast, resolving to remain in the same place and the same employment till the clock struck one; and from habitude very little incommoded by the remarks and ejaculations of Mrs.\ Allen, whose vacancy of mind and incapacity for thinking were such, that as she never talked a great deal, so she could never be entirely silent; and, therefore, while she sat at her work, if she lost her needle or broke her thread, if she heard a carriage in the street, or saw a speck upon her gown, she must observe it aloud, whether there were anyone at leisure to answer her or not. \end{sloppypar}
\hyphenation
¶Synopsis:
\hyphenation{word1 ...}
Declares allowed hyphenation points within the words in the list. The
words in that list are separated by spaces. Show permitted points for
hyphenation with an ASCII dash character, -
.
Here is an example:
\hyphenation{hat-er il-lit-e-ra-ti tru-th-i-ness}
Use lowercase letters. TeX will only hyphenate if the word matches
exactly; no inflections are tried. Multiple \hyphenation
commands accumulate.
\linebreak
& \nolinebreak
¶Synopses, one of:
\linebreak \linebreak[zero-to-four]
or one of these.
\nolinebreak \nolinebreak[zero-to-four]
Encourage or discourage a line break. The optional zero-to-four
is an integer lying between 0 and 4 that allows you to soften the
instruction. The default is 4, so that without the optional argument
these commands entirely force or prevent the break. But for instance,
\nolinebreak[1]
is a suggestion that another place may be better.
The higher the number, the more insistent the request. Both commands
are fragile (see \protect
).
Here we tell LaTeX that a good place to put a linebreak is after the standard legal text.
\boilerplatelegal{} \linebreak[2] We especially encourage applications from members of traditionally underrepresented groups.
When you issue \linebreak
, the spaces in the line are stretched
out so that the break point reaches the right margin. See \\
and \newline
, to have the spaces not stretched out.
Ordinarily LaTeX automatically takes care of breaking output into pages with its usual aplomb. But if you are writing commands, or tweaking the final version of a document, then you may need to understand how to influence its actions.
LaTeX’s algorithm for splitting a document into pages is more complex than just waiting until there is enough material to fill a page and outputting the result. Instead, LaTeX typesets more material than would fit on the page and then chooses a break that is optimal in some way (it has the smallest badness). An example of the advantage of this approach is that if the page has some vertical space that can be stretched or shrunk, such as with rubber lengths between paragraphs, then LaTeX can use that to avoid widow lines (where a new page starts with the last line of a paragraph; LaTeX can squeeze the extra line onto the first page) and orphans (where the first line of paragraph is at the end of a page; LaTeX can stretch the material of the first page so the extra line falls on the second page). Another example is where LaTeX uses available vertical shrinkage to fit on a page not just the header for a new section but also the first two lines of that section.
But LaTeX does not optimize over the entire document’s set of page breaks. So it can happen that the first page break is great but the second one is lousy; to break the current page LaTeX doesn’t look as far ahead as the next page break. So occasionally you may want to influence page breaks while preparing a final version of a document.
See Layout, for more material that is relevant to page breaking.
\clearpage
& \cleardoublepage
¶Synopsis:
\clearpage
or
\cleardoublepage
End the current page and output all of the pending floating figures and
tables (see Floats). If there are too many floats to fit on the
page then LaTeX will put in extra pages containing only floats. In
two-sided printing, \cleardoublepage
also makes the next page of
content a right-hand page, an odd-numbered page, if necessary inserting
a blank page. The \clearpage
command is robust while
\cleardoublepage
is fragile (see \protect
).
LaTeX’s page breaks are optimized so ordinarily you only use this command in a document body to polish the final version, or inside commands.
The \cleardoublepage
command will put in a blank page, but it
will have the running headers and footers. To get a really blank
page, use this command.
\let\origdoublepage\cleardoublepage \newcommand{\clearemptydoublepage}{% \clearpage {\pagestyle{empty}\origdoublepage}% }
If you want LaTeX’s standard \chapter
command to do this then
add the line \let\cleardoublepage\clearemptydoublepage
. (Of
course this affects all uses of \cleardoublepage
, not just the
one in \chapter
.)
The command \newpage
(see \newpage
) also ends the current
page, but without clearing pending floats. And, if LaTeX is in
two-column mode then \newpage
ends the current column while
\clearpage
and \cleardoublepage
end the current page.
\newpage
¶Synopsis:
\newpage
End the current page. This command is robust (see \protect
).
LaTeX’s page breaks are optimized so ordinarily you only use this command in a document body to polish the final version, or inside commands.
While the commands \clearpage
and \cleardoublepage
also
end the current page, in addition they clear pending floats
(see \clearpage
& \cleardoublepage
). And, if LaTeX is in
two-column mode then \clearpage
and \cleardoublepage
end
the current page, possibly leaving an empty column, while
\newpage
only ends the current column.
In contrast with \pagebreak
(see \pagebreak
& \nopagebreak
),
the \newpage
command will cause the new page to start right where
requested. This
Four score and seven years ago our fathers brought forth on this continent, \newpage \noindent a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.
makes a new page start after ‘continent’, and the cut-off line is
not right justified. In addition, \newpage
does not vertically
stretch out the page, as \pagebreak
does.
\enlargethispage
¶Synopsis, one of:
\enlargethispage{size} \enlargethispage*{size}
Enlarge the \textheight
for the current page. The required
argument size must be a rigid length (see Lengths). It may be
positive or negative. This command is fragile (see \protect
).
A common strategy is to wait until you have the final text of a document, and then pass through it tweaking line and page breaks. This command allows you some page size leeway.
This will allow one extra line on the current page.
\enlargethispage{\baselineskip}
The starred form \enlargesthispage*
tries to squeeze the material
together on the page as much as possible, for the common use case of
getting one more line on the page. This is often used together with an
explicit \pagebreak
.
\pagebreak
& \nopagebreak
¶Synopses:
\pagebreak \pagebreak[zero-to-four]
or
\nopagebreak \nopagebreak[zero-to-four]
Encourage or discourage a page break. The optional zero-to-four
is an integer that allows you to soften the request. The default is 4,
so that without the optional argument these commands entirely force or
prevent the break. But for instance \nopagebreak[1]
suggests to
LaTeX that another spot might be preferable. The higher the number,
the more insistent the request. Both commands are fragile
(see \protect
).
LaTeX’s page endings are optimized so ordinarily you only use these commands in a document body to polish the final version, or inside commands.
If you use these inside a paragraph, they apply to the point following the line in which they appear. So this
Four score and seven years ago our fathers brought forth on this continent, \pagebreak a new nation, conceived in Liberty, and dedicated to the proposition that all men are created equal.
does not give a page break at ‘continent’, but instead at
‘nation’, since that is where LaTeX breaks that line. In
addition, with \pagebreak
the vertical space on the page is
stretched out where possible so that it extends to the normal bottom
margin. This can look strange, and if \flushbottom
is in effect
this can cause you to get ‘Underfull \vbox (badness 10000) has
occurred while \output is active’. See \newpage
, for a command that
does not have these effects.
A declaration \samepage
and corresponding samepage
environment try to only allow breaks between paragraphs. They are not
perfectly reliable. For more on keeping material on the same page,
see the FAQ entry https://texfaq.org/FAQ-nopagebrk.)
Place a footnote at the bottom of the current page, as here.
Noël Coward quipped that having to read a footnote is like having to go downstairs to answer the door, while in the midst of making love.\footnote{% I wouldn't know, I don't read footnotes.}
You can put multiple footnotes on a page. If the footnote text becomes too long then it will flow to the next page.
You can also produce footnotes by combining the \footnotemark
and
the \footnotetext
commands, which is useful in special
circumstances.
To make bibliographic references come out as footnotes you need to include a bibliographic style with that behavior (see Using BibTeX).
\footnote
\footnotemark
\footnotetext
\footnote
¶Synopsis, one of:
\footnote{text} \footnote[number]{text}
Place a footnote text at the bottom of the current page, with a footnote marker at the current position in the text.
There are over a thousand footnotes in Gibbon's \textit{Decline and Fall of the Roman Empire}.\footnote{% After reading an early version with endnotes David Hume complained, ``One is also plagued with his Notes, according to the present Method of printing the Book'' and suggested that they ``only to be printed at the Margin or the Bottom of the Page.''}
The optional argument number allows you to specify the number of
the footnote. If you use this then LaTeX does not increment the
footnote
counter.
By default, LaTeX uses arabic numbers as footnote markers. Change
this with something like
\renewcommand{\thefootnote}{\fnsymbol{footnote}}
, which
uses a sequence of symbols (see \alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters). To make this change global put that in the preamble. If
you make the change local then you may want to reset the counter with
\setcounter{footnote}{0}
.
LaTeX determines the spacing of footnotes with two parameters.
\footnoterule
¶Produces the rule separating the main text on a page from the page’s
footnotes. Default dimensions in the standard document classes (except
slides
, where it does not appear) are: vertical thickness of
0.4pt
, and horizontal size of 0.4\columnwidth
long.
Change the rule with something like this.
% \footnoterule is expanded in vertical mode, thus \kern % commands ensure that no vertical space is created, % and the rule is separated vertically with 2pt % above the note text. \renewcommand*{\footnoterule}{% \kern -3pt % This -3 is negative \hrule width \textwidth height 1pt % of the sum of this 1 \kern 2pt} % and this 2
\footnotesep
¶The height of the strut placed at the beginning of the footnote
(see \strut
). By default, this is set to the normal strut for
\footnotesize
fonts (see Font sizes), therefore there is no
extra space between footnotes. This is ‘6.65pt’ for ‘10pt’,
‘7.7pt’ for ‘11pt’, and ‘8.4pt’ for ‘12pt’. Change
it as with \setlength{\footnotesep}{11pt}
.
The \footnote
command is fragile (see \protect
).
LaTeX’s default puts many restrictions on where you can use a
\footnote
; for instance, you cannot use it in an argument to a
sectioning command such as \chapter
(it can only be used in outer
paragraph mode; see Modes). There are some workarounds; see
following sections.
In a minipage
environment the \footnote
command uses the
mpfootnote
counter instead of the footnote
counter, so
they are numbered independently. They are shown at the bottom of the
environment, not at the bottom of the page. And by default they are
shown alphabetically. See minipage
and Footnotes in a table.
\footnotemark
¶Synopsis, one of:
\footnotemark \footnotemark[number]
Put the current footnote mark in the text. To specify associated text
for the footnote see \footnotetext
. The optional argument
number causes the command to use that number to determine the
footnote mark. This command can be used in inner paragraph mode
(see Modes).
If you use \footnotemark
without the optional argument then it
increments the footnote
counter, but if you use the optional
number then it does not. The next example produces several
consecutive footnote markers referring to the same footnote.
The first theorem\footnote{Due to Gauss.} and the second theorem\footnotemark[\value{footnote}] and the third theorem.\footnotemark[\value{footnote}]
If there are intervening footnotes then you must remember the value of
the number of the common mark. This example gives the same
institutional affiliation to both the first and third authors
(\thanks
is a version of \footnote
), by explicitly
specifying the number of the footnote (‘1’).
\title{A Treatise on the Binomial Theorem} \author{J Moriarty\thanks{University of Leeds} \and A C Doyle\thanks{Durham University} \and S Holmes\footnotemark[1]} \begin{document} \maketitle
This example accomplishes the same by using the package cleveref
.
\usepackage{cleveref}[2012/02/15] % in preamble \crefformat{footnote}{#2\footnotemark[#1]#3} ... The theorem is from Evers.\footnote{\label{fn:TE}Tinker, Evers, 1994.} The corollary is from Chance.\footnote{Evers, Chance, 1990.} But the key lemma is from Tinker.\cref{fn:TE}
It will work with the package hyperref
.
This uses a counter to remember the footnote number. The third sentence is followed by the same footnote marker as the first.
\newcounter{footnoteValueSaver} All babies are illogical.\footnote{% Lewis Carroll.}\setcounter{footnoteValueSaver}{\value{footnote}} Nobody is despised who can manage a crocodile.\footnote{% Captain Hook.} Illogical persons are despised.\footnotemark[\value{footnoteValueSaver}] Therefore, anyone who can manage a crocodile is not a baby.
\footnotetext
¶Synopsis, one of:
\footnotetext{text} \footnotetext[number]{text}
Place text at the bottom of the page as a footnote. It pairs with
\footnotemark
(see \footnotemark
) and can come anywhere after
that command, but must appear in outer paragraph mode (see Modes).
The optional argument number changes the number of the footnote
mark.
See \footnotemark
and Footnotes in a table, for usage
examples.
Putting a footnote in a section heading, as in:
\section{Full sets\protect\footnote{This material due to ...}}
causes the footnote to appear at the bottom of the page where the
section starts, as usual, but also at the bottom of the table of
contents, where it is not likely to be desired. The simplest way
to have it not appear on the table of contents is to use the optional
argument to \section
.
\section[Please]{Please\footnote{% Don't footnote in chapter and section headers!}}
No \protect
is needed in front of \footnote
here because
what gets moved to the table of contents is the optional argument.
Inside a tabular
or array
environment the \footnote
command does not work; there is a footnote mark in the table cell but
the footnote text does not appear. The solution is to use a
minipage
environment as here (see minipage
).
\begin{center} \begin{minipage}{\textwidth} \centering \begin{tabular}{l|l} \textsc{Ship} &\textsc{Book} \\ \hline \textit{HMS Sophie} &Master and Commander \\ \textit{HMS Polychrest} &Post Captain \\ \textit{HMS Lively} &Post Captain \\ \textit{HMS Surprise} &A number of books\footnote{% Starting with \textit{HMS Surprise}.} \end{tabular} \end{minipage} \end{center}
Inside a minipage
, footnote marks are lowercase letters. Change
that with something like
\renewcommand{\thempfootnote}{\arabic{mpfootnote}}
(see \alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters).
The footnotes in the prior example appear at the bottom of the
minipage
. To have them appear at the bottom of the main page, as
part of the regular footnote sequence, use the \footnotemark
and
\footnotetext
pair and make a new counter.
\newcounter{mpFootnoteValueSaver} \begin{center} \begin{minipage}{\textwidth} \setcounter{mpFootnoteValueSaver}{\value{footnote}} \centering \begin{tabular}{l|l} \textsc{Woman} &\textsc{Relationship} \\ \hline Mona &Attached\footnotemark \\ Diana Villiers &Eventual wife \\ Christine Hatherleigh Wood &Fiance\footnotemark \end{tabular} \end{minipage}% percent sign keeps footnote text close to minipage \stepcounter{mpFootnoteValueSaver}% \footnotetext[\value{mpFootnoteValueSaver}]{% Little is known other than her death.}% \stepcounter{mpFootnoteValueSaver}% \footnotetext[\value{mpFootnoteValueSaver}]{% Relationship is unresolved.} \end{center}
For a floating table
environment (see table
), use the
tablefootnote
package.
\usepackage{tablefootnote} % in preamble ... \begin{table} \centering \begin{tabular}{l|l} \textsc{Date} &\textsc{Campaign} \\ \hline 1862 &Fort Donelson \\ 1863 &Vicksburg \\ 1865 &Army of Northern Virginia\tablefootnote{% Ending the war.} \end{tabular} \caption{Forces captured by US Grant} \end{table}
The footnote appears at the page bottom and is numbered in sequence with other footnotes.
Particularly in the humanities, authors can have multiple classes of
footnotes, including having footnotes of footnotes. The package
bigfoot
extends LaTeX’s default footnote mechanism in many
ways, including allow these two, as in this example.
\usepackage{bigfoot} % in preamble \DeclareNewFootnote{Default} \DeclareNewFootnote{from}[alph] % create class \footnotefrom{} ... The third theorem is a partial converse of the second.\footnotefrom{% Noted in Wilson.\footnote{Second edition only.}}
LaTeX has support for making new commands of many different kinds.
\newcommand
& \renewcommand
\providecommand
\makeatletter
& \makeatother
\@ifstar
\newcounter
: Allocating a counter\newlength
\newsavebox
\newenvironment
& \renewenvironment
\newtheorem
\newfont
\protect
\ignorespaces & \ignorespacesafterend
xspace
package\newcommand
& \renewcommand
¶Synopses, one of (three regular forms, three starred forms):
\newcommand{\cmd}{defn} \newcommand{\cmd}[nargs]{defn} \newcommand{\cmd}[nargs][optargdefault]{defn} \newcommand*{\cmd}{defn} \newcommand*{\cmd}[nargs]{defn} \newcommand*{\cmd}[nargs][optargdefault]{defn}
or the same six possibilities with \renewcommand
instead of
\newcommand
:
\renewcommand{\cmd}{defn} \renewcommand{\cmd}[nargs]{defn} \renewcommand{\cmd}[nargs][optargdefault]{defn} \renewcommand*{\cmd}{defn} \renewcommand*{\cmd}[nargs]{defn} \renewcommand*{\cmd}[nargs][optargdefault]{defn}
Define or redefine a command (see also \DeclareRobustCommand
in
Class and package commands).
The starred form of these two forbids the arguments from containing
multiple paragraphs of text (i.e., a \par
token; in plain
TeX terms: the commands are not \long
). With the default
form, arguments can be multiple paragraphs.
These are the parameters (examples follow):
Required; \cmd
is the command name. It must begin with a
backslash, \
, and must not begin with the four character string
\end
. For \newcommand
, it must not be already defined.
For \renewcommand
, this name must already be defined.
Optional; an integer from 0 to 9, specifying the number of arguments that the command takes, including any optional argument. Omitting this argument is the same as specifying 0, meaning that the command has no arguments. If you redefine a command, the new version can have a different number of arguments than the old version.
Optional; if this argument is present then the first argument of
\cmd
is optional, with default value optargdefault
(which may be the empty string). If optargdefault is not present
then \cmd
does not take an optional argument.
That is, if \cmd
is called with a following argument in
square brackets, as in \cmd[optval]{...}...
, then
within defn the parameter #1
is set to optval.
On the other hand, if \cmd
is called without following
square brackets then within defn the parameter #1
is set
to optargdefault. In either case, the required arguments start
with #2
.
Omitting [optargdefault]
from the definition is entirely
different from giving the square brackets with empty contents, as in
[]
. The former says the command being defined takes no
optional argument, so #1
is the first required argument (if
nargs ≥ 1); the latter sets the optional argument
#1
to the empty string as the default, if no optional argument
was given in the call.
Similarly, omitting [optval]
from a call is also entirely
different from giving the square brackets with empty contents. The
former sets #1
to the value of optval (assuming the
command was defined to take an optional argument); the latter sets
#1
to the empty string, just as with any other value.
If a command is not defined to take an optional argument, but is called with an optional argument, the results are unpredictable: there may be a LaTeX error, there may be incorrect typeset output, or both.
Required; the text to be substituted for every occurrence of
\cmd
. The parameters #1
, #2
,
…, #nargs
are replaced by the values supplied when
the command is called (or by optargdefault in the case of an
optional argument not specified in the call, as just explained).
TeX ignores blanks in the source following a control word
(see Control sequence, control word and control symbol), as in ‘\cmd ’. If you want a space
there, one solution is to type {}
after the command
(‘\cmd{} ’), and another solution is to use an explicit control
space (‘\cmd\ ’).
A simple example of defining a new command:
\newcommand{\RS}{Robin Smith}
results in \RS
being
replaced by the longer text. Redefining an existing command is similar:
\renewcommand{\qedsymbol}{{\small QED}}
.
If you use \newcommand
and the command name has already been
used then you get something like ‘LaTeX Error: Command \fred
already defined. Or name \end... illegal, see p.192 of the manual’.
Similarly, If you use \renewcommand
and the command name has
not been defined then you get something like ‘LaTeX Error: \hank
undefined’.
Here the first definition creates a command with no arguments, and the second, a command with one required argument:
\newcommand{\student}{Ms~O'Leary} \newcommand{\defref}[1]{Definition~\ref{#1}}
Use the first as in I highly recommend \student{} to you
. The
second has a variable argument, so that \defref{def:basis}
expands to
Definition~\ref{def:basis}
, which ultimately expands to
something like ‘Definition~3.14’.
Similarly, but with two required arguments:
\newcommand{\nbym}[2]{$#1 \times #2$}
is invoked as
\nbym{2}{k}
.
This example has an optional argument.
\newcommand{\salutation}[1][Sir or Madam]{Dear #1:}
Then \salutation
gives ‘Dear Sir or Madam:’ while
\salutation[John]
gives ‘Dear John:’. And
\salutation[]
gives ‘Dear :’.
This example has an optional argument and two required arguments.
\newcommand{\lawyers}[3][company]{#2, #3, and~#1} I employ \lawyers[Howe]{Dewey}{Cheatem}.
The output is ‘I employ Dewey, Cheatem, and Howe.’. The optional
argument, Howe
, is associated with #1
, while
Dewey
and Cheatem
are associated with #2
and #3
. Because of the optional argument,
\lawyers{Dewey}{Cheatem}
will give the output ‘I
employ Dewey, Cheatem, and company.’.
The braces around defn do not define a group, that is, they do not
delimit the scope of the result of expanding defn. For example,
with \newcommand{\shipname}[1]{\it #1}
, in this sentence,
The \shipname{Monitor} met the \shipname{Merrimac}.
the words ‘met the’, and the period, would incorrectly be in
italics. The solution is to put another pair of braces inside the
definition: \newcommand{\shipname}[1]{{\it #1}}
.
When reading input TeX converts the stream of read characters into a
sequence of tokens. When TeX sees a backslash \
, it will
handle the following characters in a special way in order to make a
control sequence token.
The control sequences fall into two categories:
\
followed by at least one ASCII letter (A-Z
and
a-z
), followed by at least one non-letter.
\
followed by one non-letter character.
The sequence of characters so found after the \
is also called
the control sequence name.
Blanks after a control word are ignored and do not produce any
whitespace in the output (see \newcommand
& \renewcommand
and
Backslash-space, \
).
Just as the \relax
command does nothing, the following input
will simply print ‘Hello!’ :
Hel\relax lo!
This is because blanks after \relax
, including the newline, are
ignored, and blanks at the beginning of a line are also ignored
(see Leading blanks).
\providecommand
¶Synopses, one of:
\providecommand{\cmd}{defn} \providecommand{\cmd}[nargs]{defn} \providecommand{\cmd}[nargs][optargdefault]{defn} \providecommand*{\cmd}{defn} \providecommand*{\cmd}[nargs]{defn} \providecommand*{\cmd}[nargs][optargdefault]{defn}
Defines a command, as long as no command of this name already exists.
If no command of this name already exists then this has the same effect
as \newcommand
. If a command of this name already exists then
this definition does nothing. This is particularly useful in a file
that may be loaded more than once, such as a style file.
See \newcommand
& \renewcommand
, for the description of the arguments.
This example
\providecommand{\myaffiliation}{Saint Michael's College} \providecommand{\myaffiliation}{Lyc\'ee Henri IV} From \myaffiliation.
outputs ‘From Saint Michael's College.’. Unlike
\newcommand
, the repeated use of \providecommand
to (try
to) define \myaffiliation
does not give an error.
\makeatletter
& \makeatother
¶Synopsis:
\makeatletter ... definition of commands with @ in their name .. \makeatother
Use this pair when you redefine LaTeX commands that are named with an
at-sign character ‘@
’. The \makeatletter
declaration makes the at-sign character have the category code of a
letter, code 11. The \makeatother
declaration sets the
category code of the at-sign to code 12, its default value.
As TeX reads characters, it assigns each one a category code, or
catcode. For instance, it assigns the backslash
character ‘\
’ the catcode 0. Command names
consist of a category 0 character, ordinarily backslash, followed
by letters, category 11 characters (except that a command name can
also consist of a category 0 character followed by a single
non-letter symbol).
LaTeX’s source code has the convention that some commands use
@
in their name. These commands are mainly intended for package
or class writers. The convention prevents authors who are just using a
package or class from accidentally replacing such a command with one of
their own, because by default the at-sign has catcode 12.
Use the pair \makeatletter
and \makeatother
inside a
.tex file, typically in the preamble, when you are defining or
redefining commands named with @
, by having them surround your
definition. Don’t use these inside .sty or .cls files
since the \usepackage
and \documentclass
commands already
arrange that the at-sign has the character code of a letter,
catcode 11.
For a comprehensive list of macros with an at-sign in their names see https://ctan.org/pkg/macros2e.
In this example the class file has a command
\thesis@universityname
that the user wants to change. These
three lines should go in the preamble, before the
\begin{document}
.
\makeatletter \renewcommand{\thesis@universityname}{Saint Michael's College} \makeatother
\@ifstar
¶Synopsis:
\newcommand{\mycmd}{\@ifstar{\mycmd@star}{\mycmd@nostar}} \newcommand{\mycmd@nostar}[nostar-num-args]{nostar-body} \newcommand{\mycmd@star}[star-num-args]{star-body}
Many standard LaTeX environments or commands have a variant with the
same name but ending with a star character *
, an asterisk.
Examples are the table
and table*
environments and the
\section
and \section*
commands.
When defining environments, following this pattern is straightforward
because \newenvironment
and \renewenvironment
allow the
environment name to contain a star. So you just have to write
\newenvironment{myenv}
or
\newenvironment{myenv*}
and continue the definition as
usual. For commands the situation is more complex as the star not being
a letter cannot be part of the command name. As in the synopsis above,
there will be a user-called command, given above as \mycmd
, which
peeks ahead to see if it is followed by a star. For instance, LaTeX
does not really have a \section*
command; instead, the
\section
command peeks ahead. This command does not accept
arguments but instead expands to one of two commands that do accept
arguments. In the synopsis these two are \mycmd@nostar
and
\mycmd@star
. They could take the same number of arguments or a
different number, or no arguments at all. As always, in a LaTeX
document a command using an at-sign @
in its name must be
enclosed inside a \makeatletter ... \makeatother
block
(see \makeatletter
& \makeatother
).
This example of \@ifstar
defines the command \ciel
and a
variant \ciel*
. Both have one required argument. A call to
\ciel{blue}
will return "not starry blue sky" while
\ciel*{night}
will return "starry night sky".
\makeatletter \newcommand*{\ciel@unstarred}[1]{not starry #1 sky} \newcommand*{\ciel@starred}[1]{starry #1 sky} \newcommand*{\ciel}{\@ifstar{\ciel@starred}{\ciel@unstarred}} \makeatother
In the next example, the starred variant takes a different number of
arguments than the unstarred one. With this definition, Agent 007’s
``My name is \agentsecret*{Bond},
\agentsecret{James}{Bond}.''
is equivalent to entering the commands
``My name is \textsc{Bond}, \textit{James} textsc{Bond}.''
\newcommand*{\agentsecret@unstarred}[2]{\textit{#1} \textsc{#2}} \newcommand*{\agentsecret@starred}[1]{\textsc{#1}} \newcommand*{\agentsecret}{% \@ifstar{\agentsecret@starred}{\agentsecret@unstarred}}
After a command name, a star is handled similarly to an optional
argument. (This differs from environment names in which the star is
part of the name itself and as such could be in any position.) Thus,
it is technically possible to put any number of spaces between the
command and the star. Thus \agentsecret*{Bond}
and
\agentsecret *{Bond}
are equivalent. However, the
standard practice is not to insert any such spaces.
There are two alternative ways to accomplish the work of
\@ifstar
. (1) The suffix
package allows the
construct \newcommand\mycommand{unstarred-variant}
followed by
\WithSuffix\newcommand\mycommand*{starred-variant}
.
(2) LaTeX provides the xparse
package, which allows
this code:
\NewDocumentCommand\foo{s}{\IfBooleanTF#1 {starred-variant}% {unstarred-variant}% }
\newcounter
: Allocating a counter ¶Synopsis, one of:
\newcounter{countername} \newcounter{countername}[supercounter]
Globally defines a new counter named countername and initialize it to zero (see Counters).
The name countername must consist of letters only. It does not begin with a backslash. This name must not already be in use by another counter.
When you use the optional argument [supercounter]
then the
counter countername will be reset to zero whenever
supercounter is incremented. For example, ordinarily
subsection
is numbered within section
so that any time you
increment section, either with \stepcounter
(see \stepcounter
) or \refstepcounter
(see \refstepcounter
), then LaTeX will reset subsection to
zero.
This example
\newcounter{asuper} \setcounter{asuper}{1} \newcounter{asub}[asuper] \setcounter{asub}{3} % Note `asuper' The value of asuper is \arabic{asuper} and of asub is \arabic{asub}. \stepcounter{asuper} Now asuper is \arabic{asuper} while asub is \arabic{asub}.
produces ‘The value of asuper is 1 and that of asub is 3’ and ‘Now asuper is 2 while asub is 0’.
If the counter already exists, for instance by entering asuper
twice, then you get something like ‘LaTeX Error: Command \c@asuper
already defined. Or name \end... illegal, see p.192 of the manual.’.
If you use the optional argument then the super counter must already
exist. Entering \newcounter{jh}[lh]
when lh
is not a
defined counter will get you ‘LaTeX Error: No counter 'lh'
defined.’
\newlength
¶Synopsis:
\newlength{\len}
Allocate a new length register (see Lengths). The required argument
\len
has to be a control sequence (see Control sequence, control word and control symbol), and as such must begin with a backslash, \
under
normal circumstances. The new register holds rubber lengths such as
72.27pt
or 1in plus.2in minus.1in
(a LaTeX length
register is what plain TeX calls a skip
register). The
initial value is zero. The control sequence \len
must not
be already defined.
An example:
\newlength{\graphichgt}
If you forget the backslash then you get ‘Missing control sequence inserted’. If the control sequence already exists then you get something like ‘LaTeX Error: Command \graphichgt already defined. Or name \end... illegal, see p.192 of the manual’.
\newsavebox
¶Synopsis:
\newsavebox{\cmd}
Define \cmd, the string consisting of a backslash followed by
cmd, to refer to a new bin for storing material. These bins hold
material that has been typeset, to use multiple times or to measure or
manipulate (see Boxes). The bin name \cmd is required, must
start with a backslash, \, and must not already be a defined command.
This command is fragile (see \protect
).
This allocates a bin and then puts typeset material into it.
\newsavebox{\logobox} \savebox{\logobox}{LoGo} Our logo is \usebox{\logobox}.
The output is ‘Our logo is LoGo’.
If there is an already defined bin then you get something like ‘LaTeX Error: Command \logobox already defined. Or name \end... illegal, see p.192 of the manual’.
The allocation of a box is global.
\newenvironment
& \renewenvironment
¶Synopses, one of:
\newenvironment{env}{begdef}{enddef} \newenvironment{env}[nargs]{begdef}{enddef} \newenvironment{env}[nargs][optargdefault]{begdef}{enddef} \newenvironment*{env}{begdef}{enddef} \newenvironment*{env}[nargs]{begdef}{enddef} \newenvironment*{env}[nargs][optargdefault]{begdef}{enddef}
or one of these.
\renewenvironment{env}{begdef}{enddef} \renewenvironment{env}[nargs]{begdef}{enddef} \renewenvironment{env}[nargs][optargdefault]{begdef}{enddef} \renewenvironment*{env}{begdef}{enddef} \renewenvironment*{env}[nargs]{begdef}{enddef} \renewenvironment*{env}[nargs][optargdefault]{begdef}{enddef}
Define or redefine the environment env, that is, create the
construct \begin{env} ... body ... \end{env}
.
The starred form of these commands requires that the arguments not contain multiple paragraphs of text. However, the body of these environments can contain multiple paragraphs.
Required; the environment name. It consists only of letters or the
*
character, and thus does not begin with backslash, \
.
It must not begin with the string end
. For
\newenvironment
, the name env must not be the name of an
already existing environment, and also the command \env
must be undefined. For \renewenvironment
, env must be the
name of an existing environment.
Optional; an integer from 0 to 9 denoting the number of arguments of
that the environment takes. When you use the environment these
arguments appear after the \begin
, as in
\begin{env}{arg1} ... {argn}
. Omitting
this is equivalent to setting it to 0; the environment will have no
arguments. When redefining an environment, the new version can have a
different number of arguments than the old version.
Optional; if this is present then the first argument of the defined environment is optional, with default value optargdefault (which may be the empty string). If this is not in the definition then the environment does not take an optional argument.
That is, when optargdefault is present in the definition of the
environment then you can start the environment with square brackets, as
in \begin{env}[optval]{...} ... \end{env}
.
In this case, within begdefn the parameter #1
is set to the
value of optval. If you call \begin{env}
without
square brackets, then within begdefn the parameter #1
is
set to the value of the default optargdefault. In either case,
any required arguments start with #2
.
Omitting [myval]
in the call is different than having the
square brackets with no contents, as in []
. The former results
in #1
expanding to optargdefault; the latter results in
#1
expanding to the empty string.
Required; the text expanded at every occurrence of
\begin{env}
. Within begdef, the parameters
#1
, #2
, ... #nargs
, are replaced by the
values that you supply when you call the environment; see the examples
below.
Required; the text expanded at every occurrence of
\end{env}
. This may not contain any parameters, that is,
you cannot use #1
, #2
, etc., here (but see the final
example below).
All environments, that is to say the begdef code, the environment
body, and the enddef code, are processed within a group. Thus, in
the first example below, the effect of the \small
is limited to
the quote and does not extend to material following the environment.
If you try to define an environment and the name has already been used then you get something like ‘LaTeX Error: Command \fred already defined. Or name \end... illegal, see p.192 of the manual’. If you try to redefine an environment and the name has not yet been used then you get something like ‘LaTeX Error: Environment hank undefined.’.
This example gives an environment like LaTeX’s quotation
except that it will be set in smaller type.
\newenvironment{smallquote}{% \small\begin{quotation} }{% \end{quotation} }
This has an argument, which is set in boldface at the start of a paragraph.
\newenvironment{point}[1]{% \noindent\textbf{#1} }{% }
This one shows the use of a optional argument; it gives a quotation environment that cites the author.
\newenvironment{citequote}[1][Shakespeare]{% \begin{quotation} \noindent\textit{#1}: }{% \end{quotation} }
The author’s name is optional, and defaults to ‘Shakespeare’. In the document, use the environment like this.
\begin{citequote}[Lincoln] ... \end{citequote}
The final example shows how to save the value of an argument to use in
enddef, in this case in a box (see \sbox
& \savebox
).
\newsavebox{\quoteauthor} \newenvironment{citequote}[1][Shakespeare]{% \sbox\quoteauthor{#1}% \begin{quotation} }{% \hspace{1em plus 1fill}---\usebox{\quoteauthor} \end{quotation} }
\newtheorem
¶Synopses:
\newtheorem{name}{title} \newtheorem{name}{title}[numbered_within] \newtheorem{name}[numbered_like]{title}
Define a new theorem-like environment. You can specify one of numbered_within and numbered_like, or neither, but not both.
The first form, \newtheorem{name}{title}
, creates
an environment that will be labelled with title; see the first
example below.
The second form,
\newtheorem{name}{title}[numbered_within]
,
creates an environment whose counter is subordinate to the existing
counter numbered_within, so this counter will be reset when
numbered_within is reset. See the second example below.
The third form
\newtheorem{name}[numbered_like]{title}
,
with optional argument between the two required arguments, creates an
environment whose counter will share the previously defined counter
numbered_like. See the third example.
This command creates a counter named name. In addition, unless
the optional argument numbered_like is used, inside of the
theorem-like environment the current \ref
value will be that of
\thenumbered_within
(see \ref
).
This declaration is global. It is fragile (see \protect
).
Arguments:
The name of the environment. It is a string of letters. It must not
begin with a backslash, \
. It must not be the name of an
existing environment, and the command name \name
must not
already be defined.
The text to be printed at the beginning of the environment, before the number. For example, ‘Theorem’.
Optional; the name of an already defined counter, usually a sectional
unit such as chapter
or section
. When the
numbered_within counter is reset then the name environment’s
counter will also be reset.
If this optional argument is not used then the command
\thename
is set to \arabic{name}
.
Optional; the name of an already defined theorem-like environment. The new environment will be numbered in sequence with numbered_like.
Without any optional arguments the environments are numbered sequentially. The example below has a declaration in the preamble that results in ‘Definition 1’ and ‘Definition 2’ in the output.
\newtheorem{defn}{Definition} \begin{document} \section{...} \begin{defn} First def \end{defn} \section{...} \begin{defn} Second def \end{defn}
This example has the same document body as the prior one. But here
\newtheorem
’s optional argument numbered_within is given as
section
, so the output is like ‘Definition 1.1’ and
‘Definition 2.1’.
\newtheorem{defn}{Definition}[section] \begin{document} \section{...} \begin{defn} First def \end{defn} \section{...} \begin{defn} Second def \end{defn}
In the next example there are two declarations in the preamble, the
second of which calls for the new thm
environment to use the same
counter as defn
. It gives ‘Definition 1.1’, followed
by ‘Theorem 2.1’ and ‘Definition 2.2’.
\newtheorem{defn}{Definition}[section] \newtheorem{thm}[defn]{Theorem} \begin{document} \section{...} \begin{defn} First def \end{defn} \section{...} \begin{thm} First thm \end{thm} \begin{defn} Second def \end{defn}
\newfont
¶This command is obsolete. This description is here only to help with old documents. New documents should define fonts in families through the New Font Selection Scheme which allows you to, for example, associate a boldface with a roman (see Fonts).
Synopsis:
\newfont{\cmd}{font description}
Define a command \cmd
that will change the current font.
The control sequence must not already be defined. It must begin with a
backslash, \
.
The font description consists of a fontname and an optional
at clause. LaTeX will look on your system for a file named
fontname.tfm. The at clause can have the form either
at dimen
or scaled factor
, where a
factor of ‘1000’ means no scaling. For LaTeX’s purposes,
all this does is scale all the character and other font dimensions
relative to the font’s design size, which is a value defined in the
.tfm file.
This defines two equivalent fonts and typesets a few characters in each.
\newfont{\testfontat}{cmb10 at 11pt} \newfont{\testfontscaled}{cmb10 scaled 1100} \testfontat abc \testfontscaled abc
\protect
¶All LaTeX commands are either fragile or robust. A
fragile command can break when it is used in the argument to certain
other commands, typically those that write material to the table of
contents, the cross-reference file, etc. To prevent fragile
commands from causing errors, one solution is to precede them with the
command \protect
.
For example, when LaTeX runs the \section{section
name}
command it writes the section name text to the
.aux auxiliary file, moving it there for use elsewhere in the
document such as in the table of contents. Such an argument that is
used in multiple places is referred to as a
moving argument. A command is fragile if it can
expand during this process into invalid TeX code. Some examples of
moving arguments are those that appear in the \caption{...}
command (see figure
), in the \thanks{...}
command
(see \maketitle
), and in @-expressions in the tabular
and
array
environments (see tabular
).
If you get strange errors from commands used in moving arguments, try
preceding it with \protect
. Each fragile command must be
protected with their own \protect
.
Although usually a \protect
command doesn’t hurt, length
commands such as \parindent
should not be preceded by a
\protect
command (see Lengths. Nor can a \protect
command be used in the argument to \addtocounter
or
\setcounter
command (see \setcounter
and
\addtocounter
. These commands are already robust.
As of the October 2019 release of LaTeX
(https://www.latex-project.org/news/latex2e-news/ltnews30.pdf),
most commands that had been previously fragile were fixed to be
robust. For example, any command taking an optional argument, such as
\root
or \raisebox
, was fragile, but is now
robust. Similarly, \(...\)
math was fragile and is now robust
($...$
has always been robust).
Perhaps the most commonly used remaining fragile command is
\verb
; for example,
\begin{figure} ... \caption{This \verb|\command| causes an error.} \end{figure}
Adding \protect
does not help here. It’s usually feasible to
rewrite the caption (or section heading or whatever) to use
\texttt
, often the simplest solution.
Alternatively, to use \verb
, you can apply the
\cprotect
command from cprotect
package
(https://ctan.org/pkg/cprotect) to the \caption
:
\cprotect\caption{This \verb|\command| is ok with \verb|\cprotect|.}
\cprotect
also allows use of \begin...\end
environments
in moving arguments, where they are normally not allowed, via a
similar prefix command \cprotEnv
.
\ignorespaces & \ignorespacesafterend
¶Synopsis:
\ignorespaces
or
\ignorespacesafterend
Both commands cause LaTeX to ignore blanks (that is, characters of catcode 10 such as space or tabulation) after the end of the command up to the first box or non-blank character. The first is a primitive command of TeX, and the second is LaTeX-specific.
The \ignorespaces
is often used when defining commands via
\newcommand
, or \newenvironment
, or \def
. The
example below illustrates. It allows a user to show the points values
for quiz questions in the margin but it is inconvenient because, as
shown in the enumerate
list, users must not put any space between
the command and the question text.
\newcommand{\points}[1]{\makebox[0pt]{\makebox[10em][l]{#1~pts}} \begin{enumerate} \item\points{10}no extra space output here \item\points{15} extra space between the number and the `extra' \end{enumerate}
The solution is to change to this.
\newcommand{\points}[1]{% \makebox[0pt]{\makebox[10em][l]{#1~pts}}\ignorespaces}
A second example shows blanks being removed from the front of text. The
commands below allow a user to uniformly attach a title to names. But,
as given, if a title accidentally starts with a space then
\fullname
will reproduce that.
\newcommand{\honorific}[1]{\def\honorific{#1}} % remember title \newcommand{\fullname}[1]{\honorific~#1} % put title before name \begin{tabular}{|l|} \honorific{Mr/Ms} \fullname{Jones} \\ % no extra space here \honorific{ Mr/Ms} \fullname{Jones} % extra space before title \end{tabular}
To fix this, change to
\newcommand{\fullname}[1]{\ignorespaces\honorific~#1}
.
The \ignorespaces
is also often used in a \newenvironment
at the end of the begin clause, as in
\begin{newenvironment}{env
name}{... \ignorespaces}{...}
.
To strip blanks off the end of an environment use
\ignorespacesafterend
. An example is that this will show a much
larger vertical space between the first and second environments than
between the second and third.
\newenvironment{eq}{\begin{equation}}{\end{equation}} \begin{eq} e=mc^2 \end{eq} \begin{equation} F=ma \end{equation} \begin{equation} E=IR \end{equation}
Putting a comment character %
immediately after the
\end{eq}
will make the vertical space disappear, but that is
inconvenient. The solution is to change to
\newenvironment{eq}{\begin{equation}}{\end{equation}\ignorespacesafterend}
.
xspace
package ¶This is an add-on package, not part of core LaTeX. Synopsis:
\usepackage{xspace} ... \newcommand{...}{...\xspace}
The \xspace
macro, when used at the end of a command definition,
adds a space unless the command is followed by certain punctuation
characters.
After a control sequence that is a control word (see Control sequence, control word and control symbol, as opposed to control symbols such as \$
), TeX
gobbles blank characters. Thus, in the first sentence below, the
output has ‘Vermont’ placed snugly against the period, without
any intervening space, despite the space in the input.
\newcommand{\VT}{Vermont} Our college is in \VT . \VT{} summers are nice.
But because of the gobbling, the second sentence needs the empty curly
braces or else there would be no space separating ‘Vermont’ from
‘summers’. (Many authors instead use a backslash-space
\
for this. See Backslash-space, \
.)
The xspace
package provides \xspace
. It is for writing
commands which are designed to be used mainly in text. It must be placed
at the very end of the definition of these commands. It inserts a space
after that command unless what immediately follows is in a list of
exceptions. In this example, the empty braces are not needed.
\newcommand{\VT}{Vermont\xspace} Our college is in \VT . \VT summers are nice.
The default exception list contains the characters ,.'/?;:!~-)
,
the open curly brace and the backslash-space command discussed above,
and the commands \footnote
or \footnotemark
. You can
add to that list as with \xspaceaddexceptions{\myfni \myfnii}
which adds \myfni
and \myfnii
to the list; and you
can remove from that list as with \xspaceremoveexception{!}
.
A comment: many experts prefer not to use \xspace
. Putting it in
a definition means that the command will usually get the spacing right.
But it isn’t easy to predict when to enter empty braces because
\xspace
will get it wrong, such as when it is followed by another
command, and so \xspace
can make editing material harder and more
error-prone than instead of always inserting the empty braces.
These are commands designed to help writers of classes or packages.
\AtBeginDvi
& \AtEndDvi
\AtEndOfClass
& \AtEndOfPackage
\CheckCommand
\ClassError
and \PackageError
and others\CurrentOption
\DeclareOption
\DeclareRobustCommand
\ExecuteOptions
\IfFileExists
& \InputIfFileExists
\LoadClass
& \LoadClassWithOptions
\NeedsTeXFormat
\OptionNotUsed
\PassOptionsToClass
& \PassOptionsToPackage
\ProcessOptions
\ProvidesClass
& \ProvidesPackage
\ProvidesFile
\RequirePackage
& \RequirePackageWithOptions
\AtBeginDvi
& \AtEndDvi
¶Synopsis:
\AtBeginDvi{code} \AtEndDvi{code}
\AtBeginDvi
saves, in a box register, code to be executed
at the beginning of the shipout of the first page of the document.
Despite the name, it applies to DVI, PDF, and XDV output. It fills
the shipout/firstpage
hook; new code should use that hook
directly.
Similarly, \AtEndDvi
(previously available only with the
atenddvi
package) is code executed when finalizing the main
output document.
\AtEndOfClass
& \AtEndOfPackage
¶Synopses:
\AtEndOfClass{code} \AtEndOfPackage{code}
Hooks to insert code to be executed when LaTeX finishes processing the current class resp. package.
These hooks can be used multiple times; each code
segment will
be executed in the order called. Many packages and classes use these
commands.
See also \AtBeginDocument
.
\CheckCommand
¶Synopsis:
\CheckCommand{cmd}[num][default]{definition}
\CheckCommand* (same parameters)
Like \newcommand
(see \newcommand
& \renewcommand
) but does
not define cmd; instead it checks that the current definition of
cmd is exactly as given by definition and is or is not
\long
as expected. A long command is a command that
accepts \par
within an argument.
With the unstarred version of \CheckCommand
, cmd is
expected to be \long
; with the starred version, cmd must
not be \long
\CheckCommand
raises an error when the check fails. This
allows you to check before you start redefining cmd
yourself
that no other package has already redefined this command.
\ClassError
and \PackageError
and others ¶Produce error, warning, and informational messages for classes:
\ClassError{class name}{error-text}{help-text}
¶\ClassWarning{class name}{warning-text}
\ClassWarningNoLine{class name}{warning-text}
\ClassInfo{class name}{info-text}
\ClassInfoNoLine{class name}{info-text}
and the same for packages:
\PackageError{package name}{error-text}{help-text}
¶\PackageWarning{package name}{warning-text}
\PackageWarningNoLine{package name}{warning-text}
\PackageInfo{package name}{info-text}
\PackageInfoNoLine{package name}{info-text}
For \ClassError
and \PackageError
the message is
error-text, followed by TeX’s ‘?
’ error prompt. If the
user then asks for help by typing h
, they see the help
text.
The four Warning
commands are similar except that they write
warning-text on the screen with no error prompt. The four
Info
commands write info-text only in the transcript
file. The NoLine
versions omit the number of the line
generating the message, while the other versions do show that number.
To format the messages, including the help-text: use
\protect
to stop a command from expanding, get a line break
with \MessageBreak
, and get a space with \space
when a
space character is ignore, most commonly after a command.
LaTeX appends a period to the messages.
\CurrentOption
¶Expands to the name of the option currently being processed. This can
only be used within the code argument of either
\DeclareOption
or \DeclareOption*
.
\DeclareOption
¶Synopsis:
\DeclareOption{option}{code} \DeclareOption*{option}{code}
Define an option a user can include in their \documentclass
command. For example, a class smcmemo
could have an option
logo
allowing users to put the institutional logo on the first
page. The document would start with
\documentclass[logo]{smcmemo}
. To enable this, the class file
must contain \DeclareOption{logo}{code}
(and later,
\ProcessOptions
).
If you request an option that has not been declared, by default this
will produce a warning like Unused global option(s):
[badoption].
This can be changed by using
\DeclareOption*{code}
, which executes code for
any unknown option.
For example, many classes extend an existing class, using code such as
\LoadClass{article}
(see \LoadClass). In this case, it
makes sense to pass any otherwise-unknown options to the underlying
class, like this:
\DeclareOption*{% \PassOptionsToClass{\CurrentOption}{article}% }
As another example, our class smcmemo
might allow users to keep
lists of memo recipients in external files, so the user could invoke
\documentclass[math]{smcmemo}
and it will read the file
math.memo
. This code inputs the file if it exists, while if it
doesn’t, the option is passed to the article
class:
\DeclareOption*{\InputIfFileExists{\CurrentOption.memo} {}{% \PassOptionsToClass{\CurrentOption}{article}}}
\DeclareRobustCommand
¶Synopsis:
\DeclareRobustCommand{cmd}[num][default]{definition}
\DeclareRobustCommand* (same parameters
\DeclareRobustCommand
and its starred form are generally like
\newcommand
and \newcommand*
(see \newcommand
& \renewcommand
), with the addition that they define a so-called
robust command, even if some code within the definition is
fragile. (For a discussion of robust and fragile commands,
see \protect
.)
Also unlike \newcommand
, these do not give an error if macro
cmd already exists; instead, a log message is put into the
transcript file if a command is redefined. Thus,
\DeclareRobustCommand
can be used to define new robust commands
or to redefine existing commands, making them robust.
The starred form, \DeclareRobustCommand*
, disallows the
arguments from containing multiple paragraphs, just like the starred
form of \newcommand
and \renewcommand
. The meaning of
the arguments is the same.
Commands defined this way are a bit less efficient than those defined
using \newcommand
so unless the command’s data is fragile and the
command is used within a moving argument, use \newcommand
.
Related to this, the etoolbox
package offers three commands
and their starred forms: \newrobustcmd
(*
)
\renewrobustcmd
(*
), and
\providerobustcmd
(*
). They are similar to
\newcommand
, \renewcommand
, and \providecommand
and their own starred forms, but define a robust cmd. They have
two possible advantages compared to \DeclareRobustCommand
:
\protect
mechanism, so they do not incur
the slight loss of performance mentioned above, and
\new…
,
\renew…
, and \provide…
, as the standard
commands. That is, they do not just write a log message when you
redefine cmd that already exists; you need to use either
\renew…
or \provide…
, or you get an error.
This may or may not be a benefit.
\ExecuteOptions
¶Synopsis:
\ExecuteOptions{option-list}
For each option option in option-list, in order, this
command executes the command \ds@option
. If this
command is not defined then that option is silently ignored.
This can be used to provide a default option list before
\ProcessOptions
. For example, if in a class file you want the
default to be 11pt fonts then you could specify
\ExecuteOptions{11pt}\ProcessOptions\relax
.
\IfFileExists
& \InputIfFileExists
¶Synopses:
\IfFileExists{filename}{true-code}{false-code} \InputIfFileExists{filename}{true-code}{false-code}
\IfFileExists
executes true-code if LaTeX finds the
file filename or false-code otherwise. In the
first case it executing true-code and then inputs the file.
Thus the command
\IfFileExists{img.pdf}{% \includegraphics{img.pdf}} {\typeout{!! img.pdf not found}
will include the graphic img.pdf if it is found and otherwise give a warning.
This command looks for the file in all search paths that LaTeX
uses, not only in the current directory. To look only in the current
directory do something like
\IfFileExists{./filename}{true-code}{false-code}
.
If you ask for a filename without a .tex
extension then
LaTeX will first look for the file by appending the .tex
;
for more on how LaTeX handles file extensions see \input
.
\InputIfFileExists
is similar, but, as the name states,
automatically \input
s filename if it exists. The
true-code is executed just before the \input
; if the file
doesn’t exist, the false-code is executed. An example:
\InputIfFileExists{mypkg.cfg} {\PackageInfo{Loading mypkg.cfg for configuration information}} {\PackageInfo{No mypkg.cfg found}}
\LoadClass
& \LoadClassWithOptions
¶Synopses:
\LoadClass[options-list]{class-name}[release-date] \LoadClassWithOptions{class-name}[release-date]
Load a class, as with
\documentclass[options-list]{class-name}[release-date]
.
An example: \LoadClass[twoside]{article}
.
The options-list, if present, is a comma-separated list. The
release-date is also optional. If present it must have the form
YYYY/MM/DD
.
If you request release-date and the date of the package installed on your system is earlier, then you get a warning on the screen and in the log like this:
You have requested, on input line 4, version `2038/01/19' of document class article, but only version `2014/09/29 v1.4h Standard LaTeX document class' is available.
The command version \LoadClassWithOptions
uses the list of
options for the current class. This means it ignores any options passed
to it via \PassOptionsToClass
. This is a convenience command
that lets you build classes on existing ones, such as the standard
article
class, without having to track which options were passed.
\NeedsTeXFormat
¶Synopsis:
\NeedsTeXFormat{format}[format-date]
Specifies the format that this class must be run under. Often issued
as the first line of a class file, and most often used as:
\NeedsTeXFormat{LaTeX2e}
. When a document using that class
is processed, the format being run must exactly match the format
name given, including case. If it does not match then execution stops
with an error like ‘This file needs format `LaTeX2e' but this is
`plain'.’.
To require a version of the format that you know to have certain
features, include the optional format-date on which those
features were implemented. If present, it must be in the form
YYYY/MM/DD
. If the format version installed on your system is
earlier than format date then you get a warning like this.
You have requested release `2038/01/20' of LaTeX, but only release `2016/02/01' is available.
\OptionNotUsed
¶Adds the current option to the list of unused options. Can only be used
within the code argument of either \DeclareOption
or
\DeclareOption*
.
\PassOptionsToClass
& \PassOptionsToPackage
¶Synopses:
\PassOptionsToClass{options}{clsname} \PassOptionsToPackage{option}{pkgname}
Adds the options in the comma-separated list options to the
options used by any future \RequirePackage
or
\usepackage
command for the class clsname or the package
pkgname, respectively.
The reason for these commands is that although you may load a package
any number of times with no options, if you can specify options only
the first time you load the package. Loading a package with options
more than once will get you an error like Option clash for
package foo.
. LaTeX throws an error even if there is no conflict
between the options.
If your own code is bringing in a package twice then you can combine the calls; for example, replacing the two
\RequirePackage[landscape]{geometry} \RequirePackage[margins=1in]{geometry}
with the single command
\RequirePackage[landscape,margins=1in]{geometry}
However, suppose you are loading firstpkg and inside that
package it loads secondpkg, and you need secondpkg
to be
loaded with option draft
. Then before load the first package
you must tell LaTeX about the desired options for the second
package, like this:
\PassOptionsToPackage{draft}{secondpkg} \RequirePackage{firstpkg}
If firstpkg.sty
loads an option in conflict with what you want
then you may have to alter its source, or yours.
These commands are useful for general users as well as class and package
writers. For instance, suppose a user wants to load the graphicx
package with the option draft
and also wants to use a class
foo
that loads the graphicx
package, but without that
option. The user could start their LaTeX file with
\PassOptionsToPackage{draft}{graphicx} \documentclass{foo}
.
\ProcessOptions
¶Synopsis:
\ProcessOptions\@options \ProcessOptions*\@options
Execute the code for each option that the user has invoked. Invoke it
in the class file as \ProcessOptions\relax
(because of the
existence of the starred version, described below).
Options come in two types. Local options have been specified
for this particular package in \usepackage[options]
,
\RequirePackage[options]
, or the options argument
of \PassOptionsToPackage{options}
. Global options
are those given by the class user in
\documentclass[options]
. If an option is specified both
locally and globally then it is local.
When \ProcessOptions
is called for a package pkg.sty, the
following happens:
\DeclareOption
, \ProcessOptions
looks to see if that
option is either global or local for pkg
. If so, then it
executes the declared code. This is done in the order in which these
options were given in pkg.sty.
\ds@
option if it has been defined somewhere (other than by
a \DeclareOption
); otherwise, it executes the default option code
given in \DeclareOption*
. If no default option code has been
declared then it gives an error message. This is done in the order in
which these options were specified.
When \ProcessOptions
is called for a class it works in the same
way except that all options are local, and the default code for
\DeclareOption*
is \OptionNotUsed
rather than an error.
The starred version \ProcessOptions*
executes the
options in the order specified in the calling commands, rather than in
the order of declaration in the class or package. For a package, this
means that the global options are processed first.
\ProvidesClass
& \ProvidesPackage
¶Synopses:
\ProvidesClass{clsname}[release-date [info-text]] \ProvidesPackage{pkgname}[release-date [info-text]]
Identifies the class or package being defined, printing a message to the screen and the log file.
When you load a class or package, for example with
\documentclass{smcmemo}
or \usepackage{test}
,
LaTeX inputs a file (smcmemo.cls and test.sty,
respectively). If the name of the file does not match the class or
package name declared in it then you get a warning. Thus, if you
invoke \documentclass{smcmemo}
, and the file
smcmemo.cls has the statement \ProvidesClass{foo}
then
you get a warning like You have requested document class
`smcmemo', but the document class provides 'foo'.
This warning does
not prevent LaTeX from processing the rest of the class file
normally.
If you include the optional argument then you must include a date,
before any spaces, of the form YYYY/MM/DD
. The rest of the
optional argument is free-form, although it traditionally identifies
the class. It is written to the screen during compilation and to the
log file. Thus, if your file smcmemo.cls contains the line
\ProvidesClass{smcmemo}[2008/06/01 v1.0 SMC memo class]
and
your document’s first line is \documentclass{smcmemo}
then
you will see Document Class: smcmemo 2008/06/01 v1.0 SMC memo
class
.
The date in the optional argument allows class and package users to
ask to be warned if the version of the class or package is earlier
than release date. For instance, a user could enter
\documentclass{smcmemo}[2018/10/12]
or
\usepackage{foo}[[2017/07/07]]
to require a class or package
with certain features by specifying that it must be released no
earlier than the given date. Perhaps more importantly, the date
serves as documentation of the last release. (In practice, package
users rarely include a date, and class users almost never do.)
\ProvidesFile
¶Synopsis:
\ProvidesFile{filename}[info-text]
Declare a file other than the main class and package files, such as a
configuration or font definition file. It writes the given
information to the log file, essentially like \ProvidesClass
and \ProvidesPackage
(see the previous section).
For example:
\ProvidesFile{smcmemo.cfg}[2017/10/12 config file for smcmemo.cls]
writes this into the log:
File: smcmemo.cfg 2017/10/12 config file for smcmemo.cls
\RequirePackage
& \RequirePackageWithOptions
¶Synopsis:
\RequirePackage[option-list]{pkgname}[release-date] \RequirePackageWithOptions{pkgname}[release-date]
Load a package, like the command \usepackage
(see Additional packages). An example:
\RequirePackage[landscape,margin=1in]{geometry}
The initial optional argument option-list, if present, must be a
comma-separated list. The trailing optional argument
release-date, if present, must have the form YYYY/MM/DD
.
If the release date of the package as installed on your system is
earlier than release-date then you get a warning like ‘You
have requested, on input line 9, version `2017/07/03' of package
jhtest, but only version `2000/01/01' is available’.
The \RequirePackageWithOptions
variant uses the list of options
for the current class. This means it ignores any options passed to it
via \PassOptionsToClass
. This is a convenience command to
allow easily building classes on existing ones without having to track
which options were passed.
The difference between \usepackage
and \RequirePackage
is small. The \usepackage
command is intended to be used in
documents, while \RequirePackage
is intended for package and
class files. The most significant difference in practice is that
\RequirePackage
can be used in a document before the
\documentclass
command, while \usepackage
gives an error
there. The most common need for this nowadays is for the
\DocumentMetadata
command (see \DocumentMetadata
: Producing tagged PDF output).
The LaTeX development team strongly recommends use of these and
related commands over Plain TeX’s \input
; see the Class
Guide (https://ctan.org/pkg/clsguide).
Everything LaTeX numbers for you has a counter associated with
it. The name of the counter is often the same as the name of the
environment or command associated with the number, except that the
counter’s name has no backslash \
. Thus, associated with
the \chapter
command is the chapter
counter that keeps
track of the chapter number.
Below is a list of the counters used in LaTeX’s standard document classes to control numbering.
part paragraph figure enumi chapter subparagraph table enumii section page footnote enumiii subsection equation mpfootnote enumiv subsubsection
The mpfootnote
counter is used by the \footnote
command
inside of a minipage (see minipage
). The counters enumi
through enumiv
are used in the enumerate
environment, for
up to four levels of nesting (see enumerate
).
Counters can have any integer value but they are typically positive.
New counters are created with \newcounter
. See \newcounter
: Allocating a counter.
\alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters\usecounter
\value
\setcounter
\addtocounter
\refstepcounter
\stepcounter
\day
& \month
& \year
\alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters ¶Print the value of a counter, in a specified style. For instance, if
the counter counter has the value 1 then a
\alph{counter}
in your source will result in a lowercase
letter a appearing in the output.
All of these commands take a single counter as an argument, for
instance, \alph{enumi}
. Note that the counter name does not
start with a backslash.
\alph{counter}
¶Print the value of counter in lowercase letters: ‘a’, ‘b’, ... If the counter’s value is less than 1 or more than 26 then you get ‘LaTeX Error: Counter too large.’
\Alph{counter}
¶Print in uppercase letters: ‘A’, ‘B’, ... If the counter’s value is less than 1 or more than 26 then you get ‘LaTeX Error: Counter too large.’
\arabic{counter}
¶Print in Arabic numbers such as ‘5’ or ‘-2’.
\roman{counter}
¶Print in lowercase roman numerals: ‘i’, ‘ii’, ... If the counter’s value is less than 1 then you get no warning or error but LaTeX does not print anything in the output.
\Roman{counter}
¶Print in uppercase roman numerals: ‘I’, ‘II’, ... If the counter’s value is less than 1 then you get no warning or error but LaTeX does not print anything in the output.
\fnsymbol{counter}
¶Prints the value of counter using a sequence of nine symbols that are traditionally used for labeling footnotes. The value of counter should be between 1 and 9, inclusive. If the counter’s value is less than 0 or more than 9 then you get ‘LaTeX Error: Counter too large’, while if it is 0 then you get no error or warning but LaTeX does not output anything.
Here are the symbols:
Number | Name | Command | Symbol |
---|---|---|---|
1 | asterisk | \ast | * |
2 | dagger | \dagger | † |
3 | ddagger | \ddagger | ‡ |
4 | section-sign | \S | § |
5 | paragraph-sign | \P | ¶ |
6 | double-vert | \parallel | ‖ |
7 | double-asterisk | \ast\ast | ** |
8 | double-dagger | \dagger\dagger | †† |
9 | double-ddagger | \ddagger\ddagger | ‡‡ |
\usecounter
¶Synopsis:
\usecounter{counter}
Used in the second argument of the list
environment
(see list
), this declares that list items will be numbered by
counter. It initializes counter to zero, and arranges that
when \item
is called without its optional argument then
counter is incremented by \refstepcounter
, making its value
be the current ref
value (see \ref
). This command is fragile
(see \protect
).
Put in the document preamble, this example makes a new list environment enumerated with testcounter:
\newcounter{testcounter} \newenvironment{test}{% \begin{list}{}{% \usecounter{testcounter} } }{% \end{list} }
\value
¶Synopsis:
\value{counter}
Expands to the value of the counter counter. (Note that the name of a counter does not begin with a backslash.)
This example outputs ‘Test counter is 6. Other counter is 5.’.
\newcounter{test} \setcounter{test}{5} \newcounter{other} \setcounter{other}{\value{test}} \addtocounter{test}{1} Test counter is \arabic{test}. Other counter is \arabic{other}.
The \value
command is not used for typesetting the value of the
counter. For that, see \alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters.
It is often used in \setcounter
or \addtocounter
but
\value
can be used anywhere that LaTeX expects a number, such
as in \hspace{\value{foo}\parindent}
. It must not be
preceded by \protect
(see \protect
).
This example inserts \hspace{4\parindent}
.
\setcounter{myctr}{3} \addtocounter{myctr}{1} \hspace{\value{myctr}\parindent}
\setcounter
¶Synopsis:
\setcounter{counter}{value}
Globally set the counter counter to have the value of the
value argument, which must be an integer. Thus, you can set a
counter’s value as \setcounter{section}{5}
. Note that the
counter name does not start with a backslash.
In this example if the counter theorem
has value 12 then the
second line will print ‘XII’.
\setcounter{exercise}{\value{theorem}} Here it is in Roman: \Roman{exercise}.
\addtocounter
¶Synopsis:
\addtocounter{counter}{value}
Globally increment counter by the amount specified by the value argument, which may be negative.
In this example the section value appears as ‘VII’.
\setcounter{section}{5} \addtocounter{section}{2} Here it is in Roman: \Roman{section}.
\refstepcounter
¶Synopsis:
\refstepcounter{counter}
Globally increments the value of counter by one, as does
\stepcounter
(see \stepcounter
). The difference is that this
command resets the value of any counter numbered within it. (For the
definition of “counters numbered within”, see \newcounter
: Allocating a counter.)
In addition, this command also defines the current \ref
value
to be the result of \thecounter
.
While the counter value is set globally, the \ref
value is set
locally, i.e., inside the current group.
\stepcounter
¶Synopsis:
\stepcounter{counter}
Globally adds one to counter and resets all counters numbered
within it. (For the definition of “counters numbered within”,
see \newcounter
: Allocating a counter.)
This command differs from \refstepcounter
in that this one does
not influence references; that is, it does not define the current
\ref
value to be the result of \thecounter
(see \refstepcounter
).
\day
& \month
& \year
¶LaTeX defines the counter \day
for the day of the month
(nominally with value between 1 and 31), \month
for the month of
the year (nominally with value between 1 and 12), and \year
for
the year. When TeX starts up, they are set from the current values
on the system. The related command \today
produces a string
representing the current day (see \today
).
They counters are not updated as the job progresses so in principle they could be incorrect by the end. In addition, TeX does no sanity check:
\day=-2 \month=13 \year=-4 \today
gives no error or warning and results in the output ‘-2, -4’ (the bogus month value produces no output).
See Command line input, to force the date to a given value from the command line.
A length is a measure of distance. Many LaTeX commands take a length as an argument.
Lengths come in two types. A rigid length such as 10pt
does not contain a plus
or minus
component. (Plain
TeX calls this a dimen.) A rubber length (what plain
TeX calls a skip or glue) such as with 1cm
plus0.05cm minus0.01cm
can contain either or both of those
components. In that rubber length, the 1cm
is the natural
length while the other two, the plus
and minus
components, allow TeX to stretch or shrink the length to optimize
placement.
The illustrations below use these two commands.
% make a black bar 10pt tall and #1 wide \newcommand{\blackbar}[1]{\rule{#1}{10pt}} % Make a box around #2 that is #1 wide (excluding the border) \newcommand{\showhbox}[2]{% \fboxsep=0pt\fbox{\hbox to #1{#2}}}
This next example uses those commands to show a black bar 100 points long between ‘ABC’ and ‘XYZ’. This length is rigid.
ABC\showhbox{100pt}{\blackbar{100pt}}XYZ
As for rubber lengths, shrinking is simpler one: with 1cm minus
0.05cm
, the natural length is 1cm but TeX can shrink it down
as far as 0.95cm. Beyond that, TeX refuses to shrink any more.
Thus, below the first one works fine, producing a space of
98 points between the two bars.
ABC\showhbox{300pt}{% \blackbar{101pt}\hspace{100pt minus 2pt}\blackbar{101pt}}YYY ABC\showhbox{300pt}{% \blackbar{105pt}\hspace{100pt minus 1pt}\blackbar{105pt}}YYY
But the second one gets a warning like ‘Overfull \hbox (1.0pt too wide) detected at line 17’. In the output the first ‘Y’ is overwritten by the end of the black bar, because the box’s material is wider than the 300pt allocated, as TeX has refused to shrink the total to less than 309 points.
Stretching is like shrinking except that if TeX is asked to stretch beyond the given amount, it will do it. Here the first line is fine, producing a space of 110 points between the bars.
ABC\showhbox{300pt}{% \blackbar{95pt}\hspace{100pt plus 10pt}\blackbar{95pt}}YYY ABC\showhbox{300pt}{% \blackbar{95pt}\hspace{100pt plus 1pt}\blackbar{95pt}}YYY
In the second line TeX needs a stretch of 10 points and only 1 point was specified. TeX stretches the space to the required length but it gives you a warning like ‘Underfull \hbox (badness 10000) detected at line 22’. (We won’t discuss badness.)
You can put both stretch and shrink in the same length, as in
1ex plus 0.05ex minus 0.02ex
.
If TeX is setting two or more rubber lengths then it allocates the stretch or shrink in proportion.
ABC\showhbox{300pt}{% \blackbar{100pt}% left \hspace{0pt plus 50pt}\blackbar{80pt}\hspace{0pt plus 10pt}% middle \blackbar{100pt}}YYY % right
The left and right bars take up 100 points, so the middle needs
another 100. The middle bar is 80 points so the two
\hspace
’s must stretch 20 points. Because the two are
plus 50pt
and plus 10pt
, TeX gets 5/6 of the stretch
from the first space and 1/6 from the second.
The plus
or minus
component of a rubber length can contain
a fill component, as in 1in plus2fill
. This gives the
length infinite stretchability or shrinkability so that TeX could set
it to any distance. Here the two figures will be equally spaced across
the page.
\begin{minipage}{\linewidth} \hspace{0pt plus 1fill}\includegraphics{godel.png}% \hspace{0pt plus 1fill}\includegraphics{einstein.png}% \hspace{0pt plus 1fill} \end{minipage}
TeX has three levels of infinity for glue components: fil
,
fill
, and filll
. The later ones are more infinite than
the earlier ones. Ordinarily document authors only use the middle one
(see \hfill
and see \vfill
).
Multiplying a rubber length by a number turns it into a rigid length, so
that after \setlength{\ylength}{1in plus 0.2in}
and
\setlength{\zlength}{3\ylength}
then the value of
\zlength
is 3in
.
TeX and LaTeX know about these units both inside and outside of math mode.
pt
¶Point, 1/72.27 inch. The (approximate) conversion to metric units is 1point = .35146mm = .035146cm.
pc
¶Pica, 12 pt
in
¶Inch, 72.27 pt
bp
¶Big point, 1/72 inch. This length is the definition of a point in PostScript and many desktop publishing systems.
mm
¶Millimeter, 2.845pt
cm
¶Centimeter, 10mm
dd
¶Didot point, 1.07 pt
cc
¶Cicero, 12 dd
sp
¶Scaled point, 1/65536 pt
Three other units are defined according to the current font, rather than being an absolute dimension.
ex
¶The x-height of the current font ex, traditionally the height of the lowercase letter x, is often used for vertical lengths.
em
¶Similarly em, traditionally the width of the capital
letter M, is often used for horizontal lengths. This is also often
the size of the current font, e.g., a nominal 10pt font will
have 1em = 10pt. LaTeX has several commands to produce
horizontal spaces based on the em (see \enspace
& \quad
& \qquad
).
mu
¶Finally, in math mode, many definitions are expressed in terms of the math unit mu, defined by 1em = 18mu, where the em is taken from the current math symbols family. See Spacing in math mode.
Using these units can help make a definition work better across font
changes. For example, a definition of the vertical space between list
items given as \setlength{\itemsep}{1ex plus 0.05ex minus
0.01ex}
is more likely to still be reasonable if the font is changed
than a definition given in points.
\setlength
¶Synopsis:
\setlength{\len}{amount}
Set the length \len to amount. The length name
\len
has to be a control sequence (see Control sequence, control word and control symbol), and as such must begin with a backslash, \
under
normal circumstances. The amount can be a rubber length
(see Lengths). It can be positive, negative or zero, and can be in
any units that LaTeX understands (see Units of length).
Below, with LaTeX’s defaults the first paragraph will be indented while the second will not.
I told the doctor I broke my leg in two places. \setlength{\parindent}{0em} He said stop going to those places.
If you did not declare \len with \newlength
, for example if
you mistype it as in
\newlength{\specparindent}\setlength{\sepcparindent}{...}
,
then you get an error like ‘Undefined control sequence. <argument>
\sepcindent’. If you omit the backslash at the start of the length name
then you get an error like ‘Missing number, treated as zero.’.
\addtolength
¶Synopsis:
\addtolength{\len}{amount}
Increment the length \len by amount. The length name
\len
has to be a control sequence (see Control sequence, control word and control symbol), and as such must begin with a backslash, \
under
normal circumstances. The amount is a rubber length
(see Lengths). It can be positive, negative or zero, and can be in
any units that LaTeX understands (see Units of length).
Below, if \parskip
starts with the value 0pt plus 1pt
Doctor: how is the boy who swallowed the silver dollar? \addtolength{\parskip}{1pt} Nurse: no change.
then it has the value 1pt plus 1pt
for the second paragraph.
If you did not declare \len with \newlength
, for example if
you mistype it as in
\newlength{\specparindent}\addtolength{\sepcparindent}{...}
,
then you get an error like ‘Undefined control sequence. <argument>
\sepcindent’. If the amount uses some length that has not been
declared, for instance if for example you mistype the above as
\addtolength{\specparindent}{0.6\praindent}
, then you get
something like ‘Undefined control sequence. <argument> \praindent’.
If you leave off the backslash at the start of \len, as in
\addtolength{parindent}{1pt}
, then you get something like
‘You can't use `the letter p' after \advance’.
\settodepth
¶Synopsis:
\settodepth{\len}{text}
Set the length \len to the depth of box that LaTeX gets on
typesetting the text argument. The length name \len
has to be a control sequence (see Control sequence, control word and control symbol), and as such
must begin with a backslash, \
under normal circumstances.
This will print how low the character descenders go.
\newlength{\alphabetdepth} \settodepth{\alphabetdepth}{abcdefghijklmnopqrstuvwxyz} \the\alphabetdepth
If you did not declare \len with \newlength
, if for example you
mistype the above as \settodepth{\aplhabetdepth}{abc...}
,
then you get something like ‘Undefined control sequence. <argument>
\aplhabetdepth’. If you leave the backslash out of \len, as in
\settodepth{alphabetdepth}{...}
then you get something like
‘Missing number, treated as zero. <to be read again> \setbox’.
\settoheight
¶Synopsis:
\settoheight{\len}{text}
Sets the length \len to the height of box that LaTeX gets on
typesetting the text
argument. The length name \len
has to be a control sequence (see Control sequence, control word and control symbol), and as such
must begin with a backslash, \
under normal circumstances.
This will print how high the characters go.
\newlength{\alphabetheight} \settoheight{\alphabetheight}{abcdefghijklmnopqrstuvwxyz} \the\alphabetheight
If no such length \len has been declared with \newlength
, if
for example you mistype as
\settoheight{\aplhabetheight}{abc...}
, then you get something
like ‘Undefined control sequence. <argument> \alphabetheight’. If
you leave the backslash out of \len, as in
\settoheight{alphabetheight}{...}
then you get something like
‘Missing number, treated as zero. <to be read again> \setbox’.
\settowidth
¶Synopsis:
\settowidth{\len}{text}
Set the length \len to the width of the box that LaTeX gets on
typesetting the text argument. The length name \len
has to be a control sequence (see Control sequence, control word and control symbol), and as such
must begin with a backslash, \
under normal circumstances.
This prints the width of the lowercase ASCII alphabet.
\newlength{\alphabetwidth} \settowidth{\alphabetwidth}{abcdefghijklmnopqrstuvwxyz} \the\alphabetwidth
If no such length \len has been declared with \newlength
,
if for example you mistype the above as
\settowidth{\aplhabetwidth}{abc...}
, then you get something
like ‘Undefined control sequence. <argument> \aplhabetwidth’. If
you leave the backslash out of \len, as in
\settoheight{alphabetwidth}{...}
then you get something like
‘Missing number, treated as zero. <to be read again> \setbox’.
\stretch
¶Synopsis:
\stretch{number}
Produces a rubber length with zero natural length and number times
\fill
units of stretchability (see Lengths). The
number can be positive or negative. This command is robust
(see \protect
).
It works for both vertical and horizontal spacing. In this horizontal example, LaTeX produces three tick marks, and the distance between the first and second is half again as long as the distance between the second and third.
\rule{0.4pt}{1ex}\hspace{\stretch{1.5}}% \rule{0.4pt}{1ex}\hspace{\stretch{1}}% \rule{0.4pt}{1ex}
In this vertical example, the ‘We dedicate …’ will have three times as much space under it as above it.
\newenvironment{dedication}{% in document preamble \clearpage\thispagestyle{empty}% \vspace*{\stretch{1}} % stretchable space at top \it }{% \vspace{\stretch{3}} % space at bot is 3x as at top \clearpage } ... \begin{dedication} % in document body We dedicate this book to our wives. \end{dedication}
Synopsis, one of:
\numexpr expression \dimexpr expression \glueexpr expression \muglue expression
Any place where you may write an integer, or a TeX dimen, or TeX glue, or muglue, you can instead write an expression to compute that type of quantity.
An example is that \the\dimexpr\linewidth-4pt\relax
will
produce as output the length that is four points less than width of a
line (the only purpose of \the
is to show the result in the
document). Analogously, \romannumeral\numexpr6+3\relax
will
produce ‘ix’, and \the\glueexpr 5pt plus 1pt * 2 \relax
will produce ‘10.0pt plus 2.0pt’.
A convenience here over doing calculations by allocating registers and
then using \advance
, etc., is that the evaluation of expressions
does not involve assignments and can therefore be performed in places
where assignments are not allowed. The next example computes the width
of the \parbox
.
\newlength{\offset}\setlength{\offset}{2em} \begin{center} \parbox{\dimexpr\linewidth-\offset*3}{With malice toward none with charity for all with firmness in the right as God gives us to see the right let us strive on to finish the work we are in to bind up the nation's wounds, to care for him who shall have borne the battle and for his widow and his orphan \textasciitilde\ to do all which may achieve and cherish a just and lasting peace among ourselves and with all nations. ---Abraham Lincoln, Second Inaugural Address, from the memorial} \end{center}
The expression consists of one or more terms of the same type
(integer, dimension, etc.) that are added or subtracted. A term that is
a type of number, dimension, etc., consists of a factor of that type,
optionally multiplied or divided by factors. A factor of a type is
either a quantity of that type or a parenthesized subexpression. The
expression produces a result of the given type, so that \numexpr
produces an integer, \dimexpr
produces a dimension, etc.
In the quotation example above, changing to
\dimexpr\linewidth-3*\offset
gives the error Illegal unit
of measure (pt inserted)
. This is because for \dimexpr
and
\glueexpr
, the input consists of a dimension or glue value
followed by an optional multiplication factor, and not the other way
around. Thus \the\dimexpr 1pt*10\relax
is valid and produces
‘10.0pt’, but \the\dimexpr 10*1pt\relax
gives the
Illegal unit
error.
The expressions absorb tokens and carry out appropriate mathematics up
to a \relax
(which will be absorbed), or up to the first
non-valid token. Thus, \the\numexpr2+3px
will print
‘5px’, because LaTeX reads the \numexpr2+3
, which is
made up of numbers, and then finds the letter p
, which cannot
be part of a number. It therefore terminates the expression and
produces the ‘5’, followed by the regular text ‘px’.
This termination behavior is useful in comparisons. In
\ifnum\numexpr\parindent*2 < 10pt Yes\else No\fi
, the less than
sign terminates the expression and the result is ‘No’ (in a
standard LaTeX article).
Expressions may use the operators +
, -
, *
and
/
along with parentheses for subexpressions, (...)
. In
glue expressions the plus
and minus
parts do not need
parentheses to be affected by a factor. So \the\glueexpr 5pt plus
1pt * 2 \relax
results in ‘10pt plus 2pt’.
TeX will coerce other numerical types in the same way as it does when
doing register assignment. Thus \the\numexpr\dimexpr
1pt\relax\relax
will result in ‘65536’, which is 1pt
converted to scaled points (see sp
,
TeX’s internal unit) and then coerced into an integer. With a
\glueexpr
here, the stretch and shrink would be dropped. Going
the other way, a \numexpr
inside a \dimexpr
or
\glueexpr
will need appropriate units, as in
\the\dimexpr\numexpr 1 + 2\relax pt\relax
, which produces
‘3.0pt’.
The details of the arithmetic: each factor is checked to be in the
allowed range, numbers must be less than 2^{31} in absolute
value, and dimensions or glue components must be less than
2^{14} points, or mu
, or fil
, etc. The
arithmetic operations are performed individually, except for a scaling
operation (a multiplication immediately followed by a division) which
is done as one combined operation with a 64-bit product as
intermediate value. The result of each operation is again checked to
be in the allowed range.
Finally, division and scaling take place with rounding (unlike TeX’s
\divide
, which truncates). Thus
\the\dimexpr 5pt*(3/2)\relax
puts ‘10.0pt’ in the document,
because it rounds 3/2
to 2
, while
\the\dimexpr 5pt*(4/3)\relax
produces ‘5.0pt’.
To start a paragraph, just type some text. To end the current paragraph, put an empty line. This is three paragraphs, the separation of which is made by two empty lines.
It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife. However little known the feelings or views of such a man may be on his first entering a neighbourhood, this truth is so well fixed in the minds of the surrounding families, that he is considered the rightful property of some one or other of their daughters. ``My dear Mr. Bennet,'' said his lady to him one day, ``have you heard that Netherfield Park is let at last?''
A paragraph separator can be made of a sequence of at least one blank
line, at least one of which is not terminated by a comment. A blank line
is a line that is empty or made only of blank characters such as space
or tab. Comments in source code are started with a %
and span up
to the end of line. In the following example the two columns are
identical:
\documentclass[twocolumn]{article} \begin{document} First paragraph. Second paragraph. \newpage First paragraph. % separator lines may contain blank characters. Second paragraph. \end{document}
Once LaTeX has gathered all of a paragraph’s contents it divides that content into lines in a way that is optimized over the entire paragraph (see Line breaking).
There are places where a new paragraph is not permitted. Don’t put a
blank line in math mode (see Modes); here the blank line before the
\end{equation}
\begin{equation} 2^{|S|} > |S| \end{equation}
will get you the error ‘Missing $ inserted’. Similarly, the blank
line in this \section
argument
\section{aaa bbb}
gets ‘Runaway argument? {aaa ! Paragraph ended before \@sect was complete’.
\par
¶Synopsis (note that while reading the input TeX converts any sequence
of one or more blank lines to a \par
, Making paragraphs):
\par
End the current paragraph. The usual way to separate paragraphs is with
a blank line but the \par
command is entirely equivalent. This
command is robust (see \protect
).
This example uses \par
rather than a blank line simply for
readability.
\newcommand{\syllabusLegalese}{% \whatCheatingIs\par\whatHappensWhenICatchYou}
In LR mode the \par
command does nothing and is ignored. In
paragraph mode, the \par
command terminates paragraph mode,
switching LaTeX to vertical mode (see Modes).
You cannot use the \par
command in a math mode. You also cannot
use it in the argument of many commands, such as the sectioning
commands, e.g. \section
(see Making paragraphs and
\newcommand
& \renewcommand
).
The \par
command is not the same as the \paragraph
command. The latter is, like \section
or \subsection
, a
sectioning command used by the LaTeX document standard classes
(see \subsubsection
, \paragraph
, \subparagraph
).
The \par
command is not the same as \newline
or the line
break double backslash, \\
. The difference is that \par
ends the paragraph, not just the line, and also triggers the addition of
the between-paragraph vertical space \parskip
(see \parindent
& \parskip
).
The output from this example
xyz \setlength{\parindent}{3in} \setlength{\parskip}{5in} \noindent test\indent test1\par test2
is: after ‘xyz’ there is a vertical skip of 5 inches and then ‘test’ appears, aligned with the left margin. On the same line, there is an empty horizontal space of 3 inches and then ‘test1’ appears. Finally. there is a vertical space of 5 inches, followed by a fresh paragraph with a paragraph indent of 3 inches, and then LaTeX puts the text ‘test2’.
\indent
& \noindent
¶Synopsis:
\indent
or
\noindent
Go into horizontal mode (see Modes). The \indent
command
first outputs an empty box whose width is \parindent
. These
commands are robust (see \protect
).
Ordinarily you create a new paragraph by putting in a blank line.
See \par
, for the difference between this command and \par
. To
start a paragraph without an indent, or to continue an interrupted
paragraph, use \noindent
.
In the middle of a paragraph the \noindent
command has no effect,
because LaTeX is already in horizontal mode there. The
\indent
command’s only effect is to output a space.
This example starts a fresh paragraph.
... end of the prior paragraph. \noindent This paragraph is not indented.
and this continues an interrupted paragraph.
The data \begin{center} \begin{tabular}{rl} ... \end{tabular} \end{center} \noindent shows this clearly.
To omit indentation in the entire document put
\setlength{\parindent}{0pt}
in the preamble. If you do that,
you may want to also set the length of spaces between paragraphs,
\parskip
(see \parindent
& \parskip
).
Default LaTeX styles have the first paragraph after a section that is
not indented, as is traditional typesetting in English. To change that,
look on CTAN for the package indentfirst
.
\parindent
& \parskip
¶Synopsis:
\setlength{\parindent}{horizontal len} \setlength{\parskip}{vertical len}
Both are rubber lengths (see Lengths). They affect the
indentation of ordinary paragraphs, not paragraphs inside
minipages (see minipage
), and the vertical space between
paragraphs, respectively.
For example, if this is put in the preamble:
\setlength{\parindent}{0em} \setlength{\parskip}{1ex}
The document will have paragraphs that are not indented, but instead are vertically separated by about the height of a lowercase ‘x’.
In LaTeX standard class documents, the default value for
\parindent
in one-column documents is 15pt
when the
default text size is 10pt
, 17pt
for 11pt
, and
1.5em
for 12pt
. In two-column documents it is 1em
.
(These values are set before LaTeX calls \normalfont
so
em
is derived from the default font, Computer Modern. If you use
a different font then to set \parindent
to 1em matching
that font, put
\AtBeginDocument{\setlength{\parindent}{1em}}
in the
preamble.)
The default value for \parskip
in LaTeX’s standard document
classes is 0pt plus1pt
.
Synopsis, one of:
\marginpar{right} \marginpar[left]{right}
Create a note in the margin. The first line of the note will have the
same baseline as the line in the text where the \marginpar
occurs.
The margin that LaTeX uses for the note depends on the current layout
(see Document class options) and also on \reversemarginpar
(see below). If you are using one-sided layout (document option
oneside
) then it goes in the right margin. If you are using
two-sided layout (document option twoside
) then it goes in the
outside margin. If you are in two-column layout (document option
twocolumn
) then it goes in the nearest margin.
If you declare \reversemarginpar
then LaTeX will place
subsequent marginal notes in the opposite margin to that given in the
prior paragraph. Revert that to the default position with
\normalmarginpar
.
When you specify the optional argument left then it is used for a note in the left margin, while the mandatory argument right is used for a note in the right margin.
Normally, a note’s first word will not be hyphenated. You can enable
hyphenation there by beginning left or right with
\hspace{0pt}
.
These parameters affect the formatting of the note:
\marginparpush
¶Minimum vertical space between notes; default ‘7pt’ for ‘12pt’ documents, ‘5pt’ else. See also page layout parameters marginparpush.
\marginparsep
¶Horizontal space between the main text and the note; default ‘11pt’ for ‘10pt’ documents, ‘10pt’ else.
\marginparwidth
¶Width of the note itself; default for a one-sided ‘10pt’ document is ‘90pt’, ‘83pt’ for ‘11pt’, and ‘68pt’ for ‘12pt’; ‘17pt’ more in each case for a two-sided document. In two column mode, the default is ‘48pt’.
The standard LaTeX routine for marginal notes does not prevent notes from falling off the bottom of the page.
Produce mathematical text by putting LaTeX into math mode or display math mode (see Modes). This example shows both.
The wave equation for \( u \) is \begin{displaymath} \frac{\partial^2u}{\partial t^2} = c^2\nabla^2u \end{displaymath} where \( \nabla^2 \) is the spatial Laplacian and \( c \) is constant.
Math mode is for inline mathematics. In the above example it is invoked
by the starting \(
and finished by the matching ending \)
.
Display math mode is for displayed equations and here is invoked by the
displaymath
environment. Note that any mathematical text
whatever, including mathematical text consisting of just one character,
is handled in math mode.
When in math mode or display math mode, LaTeX handles many aspects of your input text differently than in other text modes. For example,
contrast x+y with \( x+y \)
in math mode the letters are in italics and the spacing around the plus sign is different.
There are three ways to make inline formulas, to put LaTeX in math mode.
\( mathematical material \) $ mathematical material $ \begin{math} mathematical material \end{math}
The first form is preferred and the second is quite common, but the
third form is rarely used. You can sometimes use one and sometimes
another, as in \(x\) and $y$
. You can use these in paragraph
mode or in LR mode (see Modes).
To make displayed formulas, put LaTeX into display math mode with either:
\begin{displaymath} mathematical material \end{displaymath}
or
\begin{equation} mathematical material \end{equation}
(see displaymath
, see equation
). The only difference is that
with the equation
environment, LaTeX puts a formula number
alongside the formula. The construct \[ math \]
is
equivalent to \begin{displaymath} math
\end{displaymath}
. These environments can only be used in paragraph
mode (see Modes).
The American Mathematical Society has made freely available a set of
packages that greatly expand your options for writing mathematics,
amsmath
and amssymb
(also be aware of the mathtools
package that is an extension to, and loads, amsmath
). New
documents that will have mathematical text should use these packages.
Descriptions of these packages is outside the scope of this document;
see their documentation on CTAN.
Synopsis (in math mode or display math mode), one of:
base^exp base^{exp}
or, one of:
base_exp base_{exp}
Make exp appear as a superscript of base (with the caret
character, ^
) or a subscript (with
underscore, _
).
In this example the 0
’s and 1
’s are subscripts while the
2
’s are superscripts.
\( (x_0+x_1)^2 \leq (x_0)^2+(x_1)^2 \)
To have the subscript or superscript contain more than one character,
surround the expression with curly braces, as in e^{-2x}
.
This example’s fourth line shows curly braces used to group an expression
for the exponent.
\begin{displaymath} (3^3)^3=27^3=19\,683 \qquad 3^{(3^3)}=3^{27}=7\,625\,597\,484\,987 \end{displaymath}
LaTeX knows how to handle a superscript on a superscript, or a
subscript on a subscript, or supers on subs, or subs on supers. So,
expressions such as e^{x^2}
and x_{i_0}
give correct
output. Note the use in those expressions of curly braces to give the
base a determined exp. If you enter \(3^3^3\)
, this
interpreted as \(3^{3}^{3}\)
and then you get TeX error
‘Double superscript’.
LaTeX does the right thing when something has both a subscript and a superscript. In this example the integral has both. They come out in the correct place without any author intervention.
\begin{displaymath} \int_{x=a}^b f'(x)\,dx = f(b)-f(a) \end{displaymath}
Note the curly braces around x=a
to make the entire expression a
subscript.
To put a superscript or subscript before a symbol, use a construct like
{}_t K^2
. The empty curly braces {}
give the
subscript something to attach to and keeps it from accidentally
attaching to a prior symbols.
Using the subscript or superscript character outside of math mode or
display math mode, as in the expression x^2
, will get you
the TeX error ‘Missing $ inserted’.
A common reason to want subscripts outside of a mathematics mode is to
typeset chemical formulas. There are packages for that, such as
mhchem
; see CTAN.
LaTeX provides almost any mathematical or technical symbol that
anyone uses. For example, if you include $\pi$
in your source,
you will get the pi symbol π. See the “Comprehensive
LaTeX Symbol List” package at
https://ctan.org/pkg/comprehensive.
Here is a list of commonly-used symbols. It is by no means exhaustive.
Each symbol is described with a short phrase, and its symbol class,
which determines the spacing around it, is given in parenthesis. Unless
said otherwise, the commands for these symbols can be used only in math
mode. To redefine a command so that it can be used whatever the current
mode, see \ensuremath
.
\|
¶∥ Parallel (relation). Synonym: \parallel
.
\aleph
¶ℵ Aleph, transfinite cardinal (ordinary).
\alpha
¶α Lowercase Greek letter alpha (ordinary).
\amalg
¶⨿ Disjoint union (binary)
\angle
¶∠ Geometric angle (ordinary). Similar: less-than
sign <
and angle bracket \langle
.
\approx
¶≈ Almost equal to (relation).
\ast
¶∗ Asterisk operator, convolution, six-pointed
(binary). Synonym: *
, which is often a superscript or
subscript, as in the Kleene star. Similar: \star
, which is
five-pointed, and is sometimes used as a general binary operation, and
sometimes reserved for cross-correlation.
\asymp
¶≍ Asymptotically equivalent (relation).
\backslash
¶\ Backslash (ordinary). Similar: set minus \setminus
, and
\textbackslash
for backslash outside of math mode.
\beta
¶β Lowercase Greek letter beta (ordinary).
\bigcap
¶⋂ Variable-sized, or n-ary, intersection (operator). Similar:
binary intersection \cap
.
\bigcirc
¶⚪ Circle, larger (binary). Similar: function
composition \circ
.
\bigcup
¶⋃ Variable-sized, or n-ary, union (operator). Similar: binary
union \cup
.
\bigodot
¶⨀ Variable-sized, or n-ary, circled dot operator (operator).
\bigoplus
¶⨁ Variable-sized, or n-ary, circled plus operator (operator).
\bigotimes
¶⨂ Variable-sized, or n-ary, circled times operator (operator).
\bigtriangledown
¶▽ Variable-sized, or n-ary, open triangle pointing down (binary). Synonym: \varbigtriangledown.
\bigtriangleup
¶△ Variable-sized, or n-ary, open triangle pointing up (binary). Synonym: \varbigtriangleup.
\bigsqcup
¶⨆ Variable-sized, or n-ary, square union (operator).
\biguplus
¶⨄ Variable-sized, or n-ary, union operator with a plus (operator). (Note that the name has only one p.)
\bigvee
¶⋁ Variable-sized, or n-ary, logical-or (operator).
\bigwedge
¶⋀ Variable-sized, or n-ary, logical-and (operator).
\bot
¶⊥, Up tack, bottom, least element of a partially ordered
set, or a contradiction (ordinary). See also \top
.
\bowtie
¶⋈ Natural join of two relations (relation).
\Box
¶□ Modal operator for necessity; square open box
(ordinary). Not available in plain TeX. In LaTeX you need to load the amssymb
package.
\bullet
¶• Bullet (binary). Similar: multiplication
dot \cdot
.
\cap
¶∩ Intersection of two sets (binary). Similar: variable-sized
operator \bigcap
.
\cdot
¶⋅ Multiplication (binary). Similar: Bullet
dot \bullet
.
\chi
¶χ Lowercase Greek chi (ordinary).
\circ
¶∘ Function composition, ring operator (binary). Similar:
variable-sized operator \bigcirc
.
\clubsuit
¶♣ Club card suit (ordinary).
\complement
¶∁, Set complement, used as a superscript as in
$S^\complement$
(ordinary). Not available in plain TeX. In LaTeX you need to load the amssymb
package. Also used:
$S^{\mathsf{c}}$
or $\bar{S}$
.
\cong
¶≅ Congruent (relation).
\coprod
¶∐ Coproduct (operator).
\cup
¶∪ Union of two sets (binary). Similar: variable-sized
operator \bigcup
.
\dagger
¶† Dagger relation (binary).
\dashv
¶⊣ Dash with vertical, reversed turnstile (relation). Similar:
turnstile \vdash
.
\ddagger
¶‡ Double dagger relation (binary).
\Delta
¶Δ Greek uppercase delta, used for increment (ordinary).
\delta
¶δ Greek lowercase delta (ordinary).
\Diamond
¶◇ Large diamond operator (ordinary). Not available in plain TeX. In LaTeX you need to load the amssymb
package.
\diamond
¶⋄ Diamond operator (binary). Similar: large
diamond \Diamond
, circle bullet \bullet
.
\diamondsuit
¶♢ Diamond card suit (ordinary).
\div
¶÷ Division sign (binary).
\doteq
¶≐ Approaches the limit (relation). Similar: geometrically equal
to \Doteq
.
\downarrow
¶↓ Down arrow, converges (relation). Similar:
\Downarrow
double line down arrow.
\Downarrow
¶⇓ Double line down arrow (relation). Similar:
\downarrow
single line down arrow.
\ell
¶ℓ Lowercase cursive letter l (ordinary).
\emptyset
¶∅ Empty set symbol (ordinary). The variant form is
\varnothing
.
\epsilon
¶ϵ Lowercase lunate epsilon (ordinary). Similar to
Greek text letter. More widely used in mathematics is the script small
letter epsilon \varepsilon
ε. Related:
the set membership relation \in
∈.
\equiv
¶≡ Equivalence (relation).
\eta
¶η Lowercase Greek letter (ordinary).
\exists
¶∃ Existential quantifier (ordinary).
\flat
¶♭ Musical flat (ordinary).
\forall
¶∀ Universal quantifier (ordinary).
\frown
¶⌢ Downward curving arc (ordinary).
\Gamma
¶Γ uppercase Greek letter (ordinary).
\gamma
¶γ Lowercase Greek letter (ordinary).
\ge
¶≥ Greater than or equal to (relation). This is a synonym
for \geq
.
\geq
¶≥ Greater than or equal to (relation). This is a synonym
for \ge
.
\gets
¶← Is assigned the value (relation).
Synonym: \leftarrow
.
\gg
¶≫ Much greater than (relation). Similar: much less
than \ll
.
\hbar
¶ℏ Planck constant over two pi (ordinary).
\heartsuit
¶♡ Heart card suit (ordinary).
\hookleftarrow
¶↩ Hooked left arrow (relation).
\hookrightarrow
¶↪ Hooked right arrow (relation).
\iff
¶⟷ If and only if (relation). It is \Longleftrightarrow
with a \thickmuskip
on either side.
\Im
¶ℑ Imaginary part (ordinary). See: real part \Re
.
\imath
¶Dotless i; used when you are putting an accent on an i (see Math accents).
\in
¶∈ Set element (relation). See also: lowercase lunate
epsilon \epsilon
ϵ and small letter script
epsilon \varepsilon
.
\infty
¶∞ Infinity (ordinary).
\int
¶∫ Integral (operator).
\iota
¶ι Lowercase Greek letter (ordinary).
\Join
¶⨝ Condensed bowtie symbol (relation). Not available in Plain TeX.
\jmath
¶Dotless j; used when you are putting an accent on a j (see Math accents).
\kappa
¶κ Lowercase Greek letter (ordinary).
\Lambda
¶Λ uppercase Greek letter (ordinary).
\lambda
¶λ Lowercase Greek letter (ordinary).
\land
¶∧ Logical and (binary). Synonym: \wedge
.
See also logical or \lor
.
\langle
¶⟨ Left angle, or sequence, bracket (opening). Similar:
less-than <
. Matches \rangle
.
\lbrace
¶{ Left curly brace
(opening). Synonym: \{
. Matches \rbrace
.
\lbrack
¶[ Left square bracket (opening).
Synonym: [
. Matches \rbrack
.
\lceil
¶⌈ Left ceiling bracket, like a square bracket but with the bottom
shaved off (opening). Matches \rceil
.
\le
¶≤ Less than or equal to (relation). This is a synonym
for \leq
.
\leadsto
¶⇝ Squiggly right arrow (relation).
To get this symbol outside of math mode you can put
\newcommand*{\Leadsto}{\ensuremath{\leadsto}}
in the
preamble and then use \Leadsto
instead.
\Leftarrow
¶⇐ Is implied by, double-line left arrow (relation). Similar:
single-line left arrow \leftarrow
.
\leftarrow
¶← Single-line left arrow (relation).
Synonym: \gets
. Similar: double-line left
arrow \Leftarrow
.
\leftharpoondown
¶↽ Single-line left harpoon, barb under bar (relation).
\leftharpoonup
¶↼ Single-line left harpoon, barb over bar (relation).
\Leftrightarrow
¶⇔ Bi-implication; double-line double-headed arrow (relation).
Similar: single-line double headed arrow \leftrightarrow
.
\leftrightarrow
¶↔ Single-line double-headed arrow (relation). Similar:
double-line double headed arrow \Leftrightarrow
.
\leq
¶≤ Less than or equal to (relation). This is a synonym
for \le
.
\lfloor
¶⌊ Left floor bracket (opening). Matches: \floor
.
\lhd
¶◁ Arrowhead, that is, triangle, pointing left (binary).
For the normal subgroup symbol you should load
amssymb
and use \vartriangleleft
(which is a relation
and so gives better spacing).
\ll
¶≪ Much less than (relation). Similar: much greater
than \gg
.
\lnot
¶¬ Logical negation (ordinary). Synonym: \neg
.
\longleftarrow
¶⟵ Long single-line left arrow (relation). Similar: long
double-line left arrow \Longleftarrow
.
\longleftrightarrow
¶⟷ Long single-line double-headed arrow (relation). Similar: long
double-line double-headed arrow \Longleftrightarrow
.
\longmapsto
¶⟼ Long single-line left arrow starting with vertical bar
(relation). Similar: shorter version \mapsto
.
\longrightarrow
¶⟶ Long single-line right arrow (relation). Similar: long
double-line right arrow \Longrightarrow
.
\lor
¶∨ Logical or (binary). Synonym: \vee
.
See also logical and \land
.
\mapsto
¶↦ Single-line left arrow starting with vertical bar
(relation).
Similar: longer version \longmapsto
.
\mho
¶℧ Conductance, half-circle rotated capital omega (ordinary).
\mid
¶∣ Single-line vertical bar (relation). A typical use of
\mid
is for a set \{\, x \mid x\geq 5 \,\}
.
Similar: \vert
and |
produce the same single-line
vertical bar symbol but without any spacing (they fall in class
ordinary) and you should not use them as relations but instead only as
ordinals, i.e., footnote symbols. For absolute value, see the entry
for \vert
and for norm see the entry for \Vert
.
\models
¶⊨ Entails, or satisfies; double turnstile, short double dash
(relation). Similar: long double dash \vDash
.
\mp
¶∓ Minus or plus (relation).
\mu
¶μ Lowercase Greek letter (ordinary).
\nabla
¶∇ Hamilton’s del, or differential, operator (ordinary).
\natural
¶♮ Musical natural notation (ordinary).
\ne
¶≠ Not equal (relation). Synonym: \neq
.
\nearrow
¶↗ North-east arrow (relation).
\neg
¶¬ Logical negation (ordinary).
Synonym: \lnot
. Sometimes instead used for
negation: \sim
.
\neq
¶≠ Not equal (relation). Synonym: \ne
.
\ni
¶∋ Reflected membership epsilon; has the member
(relation). Synonym: \owns
. Similar: is a member
of \in
.
\not
¶Long solidus, or slash, used to overstrike a following operator (relation).
Many negated operators are available that don’t require \not
,
particularly with the amssymb
package. For example, \notin
is typographically preferable to \not\in
.
\notin
¶∉ Not an element of (relation). Similar: not subset
of \nsubseteq
.
\nu
¶ν Lowercase Greek letter (ordinary).
\nwarrow
¶↖ North-west arrow (relation).
\odot
¶⊙ Dot inside a circle (binary). Similar: variable-sized
operator \bigodot
.
\oint
¶∮ Contour integral, integral with circle in the middle (operator).
\Omega
¶Ω uppercase Greek letter (ordinary).
\omega
¶ω Lowercase Greek letter (ordinary).
\ominus
¶⊖ Minus sign, or dash, inside a circle (binary).
\oplus
¶⊕ Plus sign inside a circle (binary). Similar: variable-sized
operator \bigoplus
.
\oslash
¶⊘ Solidus, or slash, inside a circle (binary).
\otimes
¶⊗ Times sign, or cross, inside a circle (binary). Similar:
variable-sized operator \bigotimes
.
\owns
¶∋ Reflected membership epsilon; has the member
(relation). Synonym: \ni
. Similar: is a member
of \in
.
\parallel
¶∥ Parallel (relation). Synonym: \|
.
\partial
¶∂ Partial differential (ordinary).
\perp
¶⟂ Perpendicular (relation). Similar: \bot
uses the
same glyph but the spacing is different because it is in the class
ordinary.
\Phi
¶Φ Uppercase Greek letter (ordinary).
\phi
¶ϕ Lowercase Greek letter (ordinary). The variant form is
\varphi
φ.
\Pi
¶Π uppercase Greek letter (ordinary).
\pi
¶π Lowercase Greek letter (ordinary). The variant form is
\varpi
ϖ.
\pm
¶± Plus or minus (binary).
\prec
¶≺ Precedes (relation). Similar: less than <
.
\preceq
¶⪯ Precedes or equals (relation). Similar: less than or
equals \leq
.
\prime
¶′ Prime, or minute in a time expression (ordinary).
Typically used as a superscript: $f^\prime$
; $f^\prime$
and $f'$
produce the same result. An advantage of the second
is that $f'''$
produces the desired symbol, that is, the same
result as $f^{\prime\prime\prime}$
, but uses rather less
typing. You can only use \prime
in math mode. Using the right
single quote '
in text mode produces a different character
(apostrophe).
\prod
¶∏ Product (operator).
\propto
¶∝ Is proportional to (relation)
\Psi
¶Ψ uppercase Greek letter (ordinary).
\psi
¶ψ Lowercase Greek letter (ordinary).
\rangle
¶⟩ Right angle, or sequence, bracket (closing).
Similar: greater than >
. Matches:\langle
.
\rbrace
¶} Right curly brace
(closing). Synonym: \}
. Matches \lbrace
.
\rbrack
¶] Right square bracket
(closing). Synonym: ]
. Matches \lbrack
.
\rceil
¶⌉ Right ceiling bracket (closing). Matches \lceil
.
\Re
¶ℜ Real part, real numbers, cursive capital R (ordinary). Related:
double-line, or blackboard bold, R \mathbb{R}
; to access
this, load the amsfonts
package.
\restriction
¶↾, Restriction of a function (relation). Synonym:
\upharpoonright
. Not available in plain TeX. In LaTeX you need to load the amssymb
package.
\revemptyset
¶⦰, Reversed empty set symbol (ordinary). Related:
\varnothing
. Not available in plain TeX. In LaTeX you need to load the stix package.
\rfloor
¶⌋ Right floor bracket, a right square bracket with the top cut
off (closing). Matches \lfloor
.
\rhd
¶◁ Arrowhead, that is, triangle, pointing right (binary).
For the normal subgroup symbol you should instead
load amssymb
and use \vartriangleright
(which is a
relation and so gives better spacing).
\rho
¶ρ Lowercase Greek letter (ordinary). The variant form is
\varrho
ϱ.
\Rightarrow
¶⇒ Implies, right-pointing double line arrow
(relation). Similar: right single-line arrow \rightarrow
.
\rightarrow
¶→ Right-pointing single line arrow (relation).
Synonym: \to
. Similar: right double line
arrow \Rightarrow
.
\rightharpoondown
¶⇁ Right-pointing harpoon with barb below the line (relation).
\rightharpoonup
¶⇀ Right-pointing harpoon with barb above the line (relation).
\rightleftharpoons
¶⇌ Right harpoon up above left harpoon down (relation).
\searrow
¶↘ Arrow pointing southeast (relation).
\setminus
¶⧵ Set difference, reverse solidus or reverse slash,
like \ (binary). Similar: backslash \backslash
and also
\textbackslash
outside of math mode.
\sharp
¶♯ Musical sharp (ordinary).
\Sigma
¶Σ uppercase Greek letter (ordinary).
\sigma
¶σ Lowercase Greek letter (ordinary). The variant form is
\varsigma
ς.
\sim
¶∼ Similar, in a relation (relation).
\simeq
¶≃ Similar or equal to, in a relation (relation).
\smallint
¶∫ Integral sign that does not change to a larger size in a display (operator).
\smile
¶⌣ Upward curving arc, smile (ordinary).
\spadesuit
¶♠ Spade card suit (ordinary).
\sqcap
¶⊓ Square intersection symbol (binary). Similar:
intersection cap
.
\sqcup
¶⊔ Square union symbol (binary). Similar:
union cup
. Related: variable-sized
operator \bigsqcup
.
\sqsubset
¶⊏, Square subset symbol (relation). Similar:
subset \subset
. Not available in plain TeX. In LaTeX you need to load the amssymb
package.
\sqsubseteq
¶⊑ Square subset or equal symbol (binary). Similar: subset or
equal to \subseteq
.
\sqsupset
¶⊐, Square superset symbol (relation). Similar:
superset \supset
. Not available in plain TeX. In LaTeX you need to load the amssymb
package.
\sqsupseteq
¶⊒ Square superset or equal symbol (binary).
Similar: superset or equal \supseteq
.
\star
¶⋆ Five-pointed star, sometimes used as a general binary
operation but sometimes reserved for cross-correlation (binary).
Similar: the synonyms asterisk *
and \ast
, which
are six-pointed, and more often appear as a superscript or subscript,
as with the Kleene star.
\subset
¶⊂ Subset (occasionally, is implied by) (relation).
\subseteq
¶⊆ Subset or equal to (relation).
\succ
¶≻ Comes after, succeeds (relation). Similar: is less
than >
.
\succeq
¶⪰ Succeeds or is equal to (relation). Similar: less
than or equal to \leq
.
\sum
¶∑ Summation (operator). Similar: Greek capital
sigma \Sigma
.
\supset
¶⊃ Superset (relation).
\supseteq
¶⊇ Superset or equal to (relation).
\surd
¶√ Radical symbol (ordinary). The LaTeX command
\sqrt{...}
typesets the square root of the argument, with a bar
that extends to cover the argument.
\swarrow
¶↙ Southwest-pointing arrow (relation).
\tau
¶τ Lowercase Greek letter (ordinary).
\theta
¶θ Lowercase Greek letter (ordinary). The variant form is
\vartheta
ϑ.
\times
¶× Primary school multiplication sign (binary). See
also \cdot
.
\to
¶→ Right-pointing single line arrow (relation).
Synonym: \rightarrow
.
\top
¶⊤ Top, greatest element of a partially ordered set
(ordinary). See also \bot
.
\triangle
¶△ Triangle (ordinary).
\triangleleft
¶◁ Not-filled triangle pointing left
(binary). Similar: \lhd
. For the normal subgroup symbol you
should load amssymb
and use \vartriangleleft
(which
is a relation and so gives better spacing).
\triangleright
¶▷ Not-filled triangle pointing right
(binary). For the normal subgroup symbol you should instead load
amssymb
and use \vartriangleright
(which is a
relation and so gives better spacing).
\unlhd
¶⊴ Left-pointing not-filled underlined arrowhead, that is,
triangle, with a line under (binary). For the
normal subgroup symbol load amssymb
and
use \vartrianglelefteq
(which is a relation and so gives
better spacing).
\unrhd
¶⊵ Right-pointing not-filled underlined arrowhead, that is,
triangle, with a line under (binary). For the
normal subgroup symbol load amssymb
and
use \vartrianglerighteq
(which is a relation and so gives
better spacing).
\Uparrow
¶⇑ Double-line upward-pointing arrow
(relation). Similar: single-line up-pointing
arrow \uparrow
.
\uparrow
¶↑ Single-line upward-pointing arrow, diverges
(relation). Similar: double-line up-pointing
arrow \Uparrow
.
\Updownarrow
¶⇕ Double-line upward-and-downward-pointing arrow
(relation). Similar: single-line upward-and-downward-pointing
arrow \updownarrow
.
\updownarrow
¶↕ Single-line upward-and-downward-pointing arrow
(relation). Similar: double-line upward-and-downward-pointing
arrow \Updownarrow
.
\upharpoonright
¶↾, Up harpoon, with barb on right side
(relation). Synonym: \restriction
.
Not available in plain TeX. In LaTeX you need to load the amssymb
package.
\uplus
¶⊎ Multiset union, a union symbol with a plus symbol in
the middle (binary). Similar: union \cup
. Related:
variable-sized operator \biguplus
.
\Upsilon
¶Υ uppercase Greek letter (ordinary).
\upsilon
¶υ Lowercase Greek letter (ordinary).
\varepsilon
¶ε Small letter script epsilon (ordinary). This is
more widely used in mathematics than the non-variant lunate epsilon form
\epsilon
ϵ. Related: set
membership \in
.
\vanothing
¶∅, Empty set symbol. Similar: \emptyset
. Related:
\revemptyset
. Not available in plain TeX. In LaTeX you need to load the amssymb
package.
\varphi
¶φ Variant on the lowercase Greek letter (ordinary).
The non-variant form is \phi
ϕ.
\varpi
¶ϖ Variant on the lowercase Greek letter (ordinary).
The non-variant form is \pi
π.
\varrho
¶ϱ Variant on the lowercase Greek letter (ordinary).
The non-variant form is \rho
ρ.
\varsigma
¶ς Variant on the lowercase Greek letter
(ordinary). The non-variant form is
\sigma
σ.
\vartheta
¶ϑ Variant on the lowercase Greek letter
(ordinary). The non-variant form is
\theta
θ.
\vdash
¶⊢ Provable; turnstile, vertical and a dash
(relation). Similar: turnstile rotated a
half-circle \dashv
.
\vee
¶∨ Logical or; a downwards v shape (binary). Related:
logical and \wedge
. Similar: variable-sized
operator \bigvee
.
\Vert
¶‖ Vertical double bar (ordinary). See Delimiters,
for how to use the mathtools
package to create flexibly-sized
norm symbols.
\vert
¶| Single line vertical bar (ordinary). For “such
that”, as in the definition of a set, use \mid
because it
is a relation. See Delimiters, for how to use the mathtools
package to create flexibly-sized absolute-value symbols.
\wedge
¶∧ Logical and (binary). Synonym: \land
. See also
logical or \vee
. Similar: variable-sized
operator \bigwedge
.
\wp
¶℘ Weierstrass p (ordinary).
\wr
¶≀ Wreath product (binary).
\Xi
¶Ξ uppercase Greek letter (ordinary).
\xi
¶ξ Lowercase Greek letter (ordinary).
\zeta
¶ζ Lowercase Greek letter (ordinary).
The following symbols are most often used in plain text but LaTeX provides versions to use in mathematical text.
\mathdollar
¶Dollar sign in math mode: $.
\mathparagraph
¶Paragraph sign (pilcrow) in math mode, ¶.
\mathsection
¶Section sign in math mode: §.
\mathsterling
¶Sterling sign in math mode: £.
\mathunderscore
¶Underscore in math mode: _.
\boldmath
& \unboldmath
These are the arrows that come with standard LaTeX. The
latexsym
and amsfonts
packages contain many more.
Symbol | Command | |
---|---|---|
⇓ | \Downarrow | |
↓ | \downarrow | |
↩ | \hookleftarrow | |
↪ | \hookrightarrow | |
← | \leftarrow | |
⇐ | \Leftarrow | |
⇔ | \Leftrightarrow | |
↔ | \leftrightarrow | |
⟵ | \longleftarrow | |
⟸ | \Longleftarrow | |
⟷ | \longleftrightarrow | |
⟺ | \Longleftrightarrow | |
⟼ | \longmapsto | |
⟹ | \Longrightarrow | |
⟶ | \longrightarrow | |
↦ | \mapsto | |
↗ | \nearrow | |
↖ | \nwarrow | |
⇒ | \Rightarrow | |
→ | \rightarrow , or \to | |
↘ | \searrow | |
↙ | \swarrow | |
↑ | \uparrow | |
⇑ | \Uparrow | |
↕ | \updownarrow | |
⇕ | \Updownarrow |
An example of the difference between \to
and \mapsto
is: \( f\colon D\to C \) given by \( n\mapsto n^2 \)
.
For commutative diagrams there are a number of packages, including
tikz-cd
and amscd
.
\boldmath
& \unboldmath
¶Synopsis (used in paragraph mode or LR mode):
\boldmath \( math \)
or
\unboldmath \( math \)
Declarations to change the letters and symbols in math to be in
a bold font, or to countermand that and bring back the regular
(non-bold) default, respectively. They must be used when not in
math mode or display math mode (see Modes). Both commands are
fragile (see \protect
).
In this example each \boldmath
command takes place inside an
\mbox
,
we have $\mbox{\boldmath \( v \)} = 5\cdot\mbox{\boldmath \( u \)$}$
which means \boldmath
is only called in a text mode, here LR
mode, and explains why we must switch LaTeX into math mode to set
v
and u
.
If you use either command inside math mode, as with Trouble: \(
\boldmath x \)
, then you get something like ‘LaTeX Font Warning:
Command \boldmath invalid in math mode’ and ‘LaTeX Font Warning:
Command \mathversion invalid in math mode’.
bm
: Individual bold math symbols ¶Specifying \boldmath
is the best method for typesetting a whole
math expression in bold. But to typeset individual symbols within an
expression in bold, the bm
package provided by the LaTeX
Project team is better. Its usage is outside the scope of this
document (see its documentation at https://ctan.org/pkg/bm or in
your installation) but the spacing in the output of this small example
will show that it is an improvement over \boldmath
within an
expression:
\usepackage{bm} % in preamble ... we have $\bm{v} = 5\cdot\bm{u}$
Unfortunately, when using the Unicode engines (XeLaTeX,
LuaLaTeX), neither \boldmath
nor bm
usually work
well, because the OpenType math fonts normally used with those engines
rarely come with a bold companion, and both \boldmath
and
bm
require this. (The implementation of bm
relies
on \boldmath
, so the requirements are the same.) If you do have
a bold math font, though, then \boldmath
and bm
work
fine.
If no such font is available, one alternative is to construct fake
bold fonts with the fontspec
package’s FakeBold=1
parameter (see its documentation,
https://ctan.org/pkg/fontspec). This may be acceptable for
drafting or informal distribution, but the results are far from a true
bold font.
Another alternative to handling bold for OpenType math fonts is to use
the \symbf
(bold), \symbfit
(bold italic), and related
commands from the unicode-math
package. These do not change
the current font, but rather change the (Unicode) “alphabet” used,
which in practice is more widely supported than a separate bold font.
Many variations are possible, and so there are subtleties to getting the
desired output. As usual, see the package documentation
(https://ctan.org/pkg/unicode-math).
Synopsis:
\usepackage{amssymb} % in preamble ... \mathbb{uppercase-letter}
Provide blackboard bold symbols, sometimes also known as doublestruck letters, used to denote number sets such as the natural numbers, the integers, etc.
Here
\( \forall n \in \mathbb{N}, n^2 \geq 0 \)
the \mathbb{N}
gives blackboard bold symbol ℕ,
representing the natural numbers.
If the argument contains something other than an uppercase letter, you do not get an error but you do get strange results, including unexpected characters.
There are packages that give access to symbols other than just the capital letters; look on CTAN.
Synopsis:
\mathcal{uppercase-letters}
Use a script-like font.
In this example the graph identifier is output in a cursive font.
Let the graph be \( \mathcal{G} \).
If you use something other than an uppercase letter then you do not get
an error but you also do not get math calligraphic output. For instance,
\mathcal{g}
outputs a close curly brace symbol.
Delimiters are parentheses, braces, or other characters used to mark the start and end of subformulas. This formula has three sets of parentheses delimiting the three subformulas.
(z-z_0)^2 = (x-x_0)^2 + (y-y_0)^2
The delimiters do not need to match, so you can enter \( [0,1) \)
.
Here are the common delimiters:
Delimiter | Command | Name |
---|---|---|
( | ( | Left parenthesis |
) | ) | Right parenthesis |
\} | { or \lbrace | Left brace |
\{ | } or \rbrace | Right brace |
[ | [ or \lbrack | Left bracket |
] | ] or \rbrack | Right bracket |
⌊ | \lfloor | Left floor bracket |
⌋ | \rfloor | Right floor bracket |
⌈ | \lceil | Left ceiling bracket |
⌉ | \rceil | Right ceiling bracket |
⟨ | \langle | Left angle bracket |
⟩ | \rangle | Right angle bracket |
/ | / | Slash, or forward slash |
\ | \backslash | Reverse slash, or backslash |
| | | or \vert | Vertical bar |
‖ | \| or \Vert | Double vertical bar |
The mathtools
package allows you to create commands for paired
delimiters. For instance, if you put
\DeclarePairedDelimiter\abs{\lvert}{\rvert}
in your preamble
then you get two commands for single-line vertical bars (they only work
in math mode). The starred form, such as
\abs*{\frac{22}{7}}
, has the height of the vertical bars
match the height of the argument. The unstarred form, such as
\abs{\frac{22}{7}}
, has the bars fixed at a default height.
This form accepts an optional argument, as in \abs[size
command]{\frac{22}{7}}
, where the height of the bars is given in
size command, such as \Bigg
. Using instead \lVert
and \rVert
as the symbols will give you a norm symbol with the
same behavior.
\left
& \right
¶Synopsis:
\left delimiter1 ... \right delimiter2
Make matching parentheses, braces, or other delimiters. LaTeX makes the delimiters tall enough to just cover the size of the formula that they enclose.
This makes a unit vector surrounded by parentheses tall enough to cover the entries.
\begin{equation} \left(\begin{array}{c} 1 \\ 0 \\ \end{array}\right) \end{equation}
See Delimiters, for a list of the common delimiters.
Every \left
must have a matching \right
. In the above
example, leaving out the \left(
gets the error message
‘Extra \right’. Leaving out the \right)
gets ‘You
can't use `\eqno' in math mode’.
However, delimiter1 and delimiter2 need not match. A common case is that you want an unmatched brace, as below. Use a period, ‘.’, as a null delimiter.
\begin{equation} f(n)=\left\{\begin{array}{ll} 1 &\mbox{--if \(n=0\)} \\ f(n-1)+3n^2 &\mbox{--else} \end{array}\right. \end{equation}
Note that to get a curly brace as a delimiter you must prefix it with a
backslash, \{
(see Reserved characters). (The packages
amsmath
and mathtools
allow you to get the above
construct through in a cases
environment.)
The \left ... \right
pair make a group. One consequence is that
the formula enclosed in the \left ... \right
pair cannot have
line breaks in the output. This includes both manual line breaks and
LaTeX-generated automatic ones. In this example, LaTeX breaks the
equation to make the formula fit the margins.
Lorem ipsum dolor sit amet \( (a+b+c+d+e+f+g+h+i+j+k+l+m+n+o+p+q+r+s+t+u+v+w+x+y+z) \)
But with \left
and \right
Lorem ipsum dolor sit amet \( \left(a+b+c+d+e+f+g+h+i+j+k+l+m+n+o+p+q+r+s+t+u+v+w+x+y+z\right) \)
LaTeX won’t break the line, causing the formula to extend into the margin.
Because \left ... \right
make a group, all the usual grouping
rules hold. Here, the value of \testlength
set inside the
equation will be forgotten, and the output is ‘1.2pt’.
\newlength{\testlength} \setlength{\testlength}{1.2pt} \begin{equation} \left( a+b=c \setlength{\testlength}{3.4pt} \right) \the\testlength \end{equation}
The \left ... \right
pair affect the horizontal spacing of the
enclosed formula, in two ways. The first is that in \( \sin(x) =
\sin\left(x\right) \)
the one after the equals sign has more space
around the x
. That’s because \left( ... \right)
inserts
an inner node while ( ... )
inserts an opening node. The second
way that the pair affect the horizontal spacing is that because they
form a group, the enclosed subformula will be typeset at its natural
width, with no stretching or shrinking to make the line fit better.
TeX scales the delimiters according to the height and depth of the enclosed formula. Here LaTeX grows the brackets to extend the full height of the integral.
\begin{equation} \left[ \int_{x=r_0}^{\infty} -G\frac{Mm}{r^2}\, dr \right] \end{equation}
Manual sizing is often better. For instance, although below the rule has no depth, TeX will create delimiters that extend far below the rule.
\begin{equation} \left( \rule{1pt}{1cm} \right) \end{equation}
TeX can choose delimiters that are too small, as in \( \left|
|x|+|y| \right| \)
. It can also choose delimiters that are too large,
as here.
\begin{equation} \left( \sum_{0\leq i<n} i^k \right) \end{equation}
A third awkward case is when a long displayed formula is on more than
one line and you must match the sizes of the opening and closing
delimiter; you can’t use \left
on the first line and
\right
on the last because they must be paired.
To size the delimiters manually, see \bigl
, \bigr
, etc..
\bigl
, \bigr
, etc. ¶Synopsis, one of:
\bigldelimiter1 ... \bigrdelimiter2 \Bigldelimiter1 ... \bigrdelimiter2 \biggldelimiter1 ... \biggrdelimiter2 \Biggldelimiter1 ... \Biggrdelimiter2
(as with \bigl[...\bigr]
; strictly speaking they need not be
paired, see below), or one of:
\bigmdelimiter \Bigmdelimiter \biggmdelimiter \Biggmdelimiter
(as with \bigm|
), or one of:
\bigdelimiter \Bigdelimiter \biggdelimiter \Biggdelimiter
(as with \big[
).
Produce manually-sized delimiters. For delimiters that are
automatically sized see \left
& \right
).
This produces slightly larger outer vertical bars.
\bigl| |x|+|y| \bigr|
The commands above are listed in order of increasing size. You can use
the smallest size such as \bigl...\bigr
in a paragraph without
causing LaTeX to spread the lines apart. The larger sizes are meant
for displayed equations.
See Delimiters, for a list of the common delimiters. In the family of commands with ‘l’ or ‘r’, delimiter1 and delimiter2 need not match together.
The ‘l’ and ‘r’ commands produce open and close delimiters that insert no horizontal space between a preceding atom and the delimiter, while the commands without ‘l’ and ‘r’ insert some space (because each delimiter is set as an ordinary variable). Compare these two.
\begin{tabular}{l} \(\displaystyle \sin\biggl(\frac{1}{2}\biggr) \) \\ % good \(\displaystyle \sin\bigg(\frac{1}{2}\bigg) \) \\ % bad \end{tabular}
The traditional typographic treatment is on the first line. On the
second line the output will have some extra space between the
\sin
and the open parenthesis.
Commands without ‘l’ or ‘r’ do give correct spacing in some circumstances, as with this large vertical line
\begin{equation} \int_{x=a}^b x^2\,dx = \frac{1}{3} x^3 \Big|_{x=a}^b \end{equation}
(many authors would replace \frac
with the \tfrac
command
from the amsmath
package), and as with this larger slash.
\begin{equation} \lim_{n\to\infty}\pi(n) \big/ (n/\log n) = 1 \end{equation}
Unlike the \left...\right
pair (see \left
& \right
), the
commands here with ‘l’ or ‘r’ do not make a group.
Strictly speaking they need not be matched so you can write something
like this.
\begin{equation} \Biggl[ \pi/6 ] \end{equation}
The commands with ‘m’ are for relations, which are in the middle of formulas, as here.
\begin{equation} \biggl\{ a\in B \biggm| a=\sum_{0\leq i<n}3i^2+4 \biggr\} \end{equation}
Ellipses are the three dots (usually three) indicating that a pattern continues.
\begin{array}{cccc} a_{0,0} &a_{0,1} &a_{0,2} &\ldots \\ a_{1,0} &\ddots \\ \vdots \end{array}
LaTeX provides these.
\cdots
¶Horizontal ellipsis with the dots raised to the center of the line, as
in ⋯. Used as: \( a_0\cdot a_1\cdots a_{n-1}
\)
.
\ddots
¶Diagonal ellipsis, ⋱. See the above array example for a usage.
\ldots
¶\mathellipsis
¶\dots
¶Ellipsis on the baseline, …. Used as: \(
x_0,\ldots x_{n-1} \)
. Another example is the above array example.
Synonyms are \mathellipsis
and \dots
. A synonym from
the amsmath
package is \hdots
.
You can also use this command outside of mathematical text, as in
The gears, brakes, \ldots{} are all broken
.
\vdots
¶Vertical ellipsis, ⋮. See the above array example for a usage.
The amsmath
package has the command \dots
to semantically
mark up ellipses. This example produces two different-looking outputs
for the first two uses of the \dots
command.
\usepackage{amsmath} % in preamble ... Suppose that \( p_0, p_1, \dots, p_{n-1} \) lists all of the primes. Observe that \( p_0\cdot p_1 \dots \cdot p_{n-1} +1 \) is not a multiple of any \( p_i \). Conclusion: there are infinitely many primes \( p_0, p_1, \dotsc \).
In the first line LaTeX looks to the comma following \dots
to
determine that it should output an ellipsis on the baseline. The second
line has a \cdot
following \dots
so LaTeX outputs an
ellipsis that is on the math axis, vertically centered. However, the
third usage has no follow-on character so you have to tell LaTeX what
to do. You can use one of the commands: \dotsc
if you need the
ellipsis appropriate for a comma following, \dotsb
if you need
the ellipses that fits when the dots are followed by a binary operator
or relation symbol, \dotsi
for dots with integrals, or
\dotso
for others.
The \dots
command from amsmath
differs from the
LaTeX kernel’s \dots
command in another way: it outputs a
thin space after the ellipsis. Furthermore, the unicode-math
package automatically loads amsmath
, so amsmath
’s
\dots
may be active even when you did not explicitly load it,
thus changing the output from \dots
in both text and math mode.
Yet more about the ellipsis commands: when running under Unicode
engines (lualatex
, xelatex
), LaTeX will use the
Unicode ellipsis character (U+2026) in the font if it’s available;
under traditional TeX engines (pdflatex
, latex
), it
will typeset three spaced periods. Generally, the Unicode
single-character ellipsis has almost no space between the three
periods, while the spacing of the non-Unicode ellipsis is looser, more
in accordance with traditional typography.
The upper case versions of these Greek letters are only shown when they differ from Roman upper case letters.
Symbol | Command | Name | |
---|---|---|---|
α | \alpha | Alpha | |
β | \beta | Beta | |
γ, Γ | \gamma , \Gamma | Gamma | |
δ, Δ | \delta , \Delta | Delta | |
ε, ϵ | \varepsilon , \epsilon | Epsilon | |
ζ | \zeta | Zeta | |
η | \eta | Eta | |
θ, ϑ | \theta , \vartheta | Theta | |
ι | \iota | Iota | |
κ | \kappa | Kappa | |
λ, Λ | \lambda , \Lambda | Lambda | |
μ | \mu | Mu | |
ν | \nu | Nu | |
ξ, Ξ | \xi , \Xi | Xi | |
π, Π | \pi , \Pi | Pi | |
ρ, ϱ | \rho , \varrho | Rho | |
σ, Σ | \sigma , \Sigma | Sigma | |
τ | \tau | Tau | |
ϕ, φ, Φ | \phi , \varphi , \Phi | Phi | |
χ | \chi | chi | |
ψ, Ψ | \psi , \Psi | Psi | |
ω, Ω | \omega , \Omega | Omega |
For omicron, if you are using LaTeX’s default Computer Modern font
then enter omicron just as ‘o’ or ‘O’. If you like having the
name or if your font shows a difference then you can use something like
\newcommand\omicron{o}
. The package unicode-math
has
\upomicron
for upright omicron and \mitomicron
for math
italic.
While the set membership relation symbol ∈ generated by
\in
is related to epsilon, it is never used for a variable.
These commands produce roman function names in math mode with proper spacing.
\arccos
¶Inverse cosine
\arcsin
¶Inverse sine
\arctan
¶Inverse tangent
\arg
¶Angle between the real axis and a point in the complex plane
\bmod
¶Binary modulo operator, used as in \( 5\bmod 3=2 \)
\cos
¶Cosine
\cosh
¶Hyperbolic cosine
\cot
¶Cotangent
\coth
¶Hyperbolic cotangent
\csc
¶Cosecant
\deg
¶Degrees
\det
¶Determinant
\dim
¶Dimension
\exp
¶Exponential
\gcd
¶Greatest common divisor
\hom
¶Homomorphism
\inf
¶Infimum
\ker
¶Kernel
\lg
¶Base 2 logarithm
\lim
¶Limit
\liminf
¶Limit inferior
\limsup
¶Limit superior
\ln
¶Natural logarithm
\log
¶Logarithm
\max
¶Maximum
\min
¶Minimum
\pmod
¶Parenthesized modulus, as used in \( 5\equiv 2\pmod 3 \)
\Pr
¶Probability
\sec
¶Secant
\sin
¶Sine
\sinh
¶Hyperbolic sine
\sup
¶Supremum sup
\tan
¶Tangent
\tanh
¶Hyperbolic tangent
The amsmath
package adds improvements on some of these, and
also allows you to define your own. The full documentation is on CTAN,
but briefly, you can define an identity operator with
\DeclareMathOperator{\identity}{id}
that is like the ones
above but prints as ‘id’. The starred form
\DeclareMathOperator*{\op}{op}
sets any superscript or
subscript to be above and below, as is traditional with \lim
,
\sup
, or \max
.
LaTeX provides a variety of commands for producing accented letters in math. These are different from accents in normal text (see Accents).
\acute
¶Math acute accent
\bar
¶Math bar-over accent
\breve
¶Math breve accent
\check
¶Math háček (check) accent
\ddot
¶Math dieresis accent
\dot
¶Math dot accent
\grave
¶Math grave accent
\hat
¶Math hat (circumflex) accent
\mathring
¶Math ring accent
\tilde
¶Math tilde accent
\vec
¶Math vector symbol
\widehat
¶Math wide hat accent
\widetilde
¶Math wide tilde accent
When you are putting an accent on an i or a j, the tradition is to use
one without a dot, \imath
or jmath
(see Math symbols).
LaTeX provides commands for putting lines, braces, and arrows over or under math material.
\underline{math}
¶Underline math. For example: \underline{x+y}
.
The line is always completely below the text, taking account of
descenders, so in \(\underline{y}\)
the line is lower than in
\(\underline{x}\)
. As of approximately 2019, this command
and others in this section are robust; before that, they were fragile
(see \protect
).
The package ulem
(https://ctan.org/pkg/uelem) does
text mode underlining and allows line breaking as well as a number of
other features. See also \hrulefill
& \dotfill
for
producing a line for such things as a signature or placeholder.
\overline{math}
¶Put a horizontal line over math. For example: \overline{x+y}
.
This differs from the accent command \bar
(see Math accents).
\underbrace{math}
¶Put a brace under math. For example:
(1-\underbrace{1/2)+(1/2}-1/3)
.
You can attach text to the brace as a subscript (_
) or
superscript (^
) as here:
\begin{displaymath} 1+1/2+\underbrace{1/3+1/4}_{>1/2}+ \underbrace{1/5+1/6+1/7+1/8}_{>1/2}+\cdots \end{displaymath}
The superscript appears on top of the expression, and so can look unconnected to the underbrace.
\overbrace{math}
¶Put a brace over math. For example:
\overbrace{x+x+\cdots+x}^{\mbox{\(k\) times}}
.
\overrightarrow{math}
¶Put a right arrow over math. For example:
\overrightarrow{x+y}
.
\overleftarrow{math}
¶Put a left arrow over math. For example:
\overleftarrow{a+b}
.
The package mathtools
(https://ctan.org/pkg/mathtools)
adds an over- and underbracket, as well as some improvements on the
braces.
When typesetting mathematics, LaTeX puts in spacing according to the
normal rules for mathematics texts. If you enter y=m x
then
LaTeX ignores the space and in the output the m is next to the x,
as y=mx.
But LaTeX’s rules occasionally need tweaking. For example, in an
integral the tradition is to put a small extra space between the
f(x)
and the dx
, here done with the \,
command:
\int_0^1 f(x)\,dx
LaTeX provides the commands that follow for use in math mode. Many
of these spacing definitions are expressed in terms of the math unit
mu. It is defined as 1/18em, where the em is taken from the
current math symbols family (see Units of length). Thus, a
\thickspace
is something like 5/18 times the width of
a ‘M’.
\;
¶Synonym: \thickspace
. Normally 5.0mu plus 5.0mu
. With
the amsmath
package, or as of the 2020-10-01 LaTeX release,
can be used in text mode as well as math mode; otherwise, in math mode
only.
\negthickspace
¶Normally -5.0mu plus 2.0mu minus 4.0mu
. With the amsmath
package, or as of the 2020-10-01 LaTeX release, can be used in text
mode as well as math mode; otherwise, in math mode only.
\:
¶\>
Synonym: \medspace
. Normally 4.0mu plus 2.0mu minus
4.0mu
. With the amsmath
package, or as of the 2020-10-01
LaTeX release, can be used in text mode as well as math mode; before
that, in math mode only.
\negmedspace
¶Normally -4.0mu plus 2.0mu minus 4.0mu
. With the amsmath
package, or as of the 2020-10-01 LaTeX release, can be used in text
mode as well as math mode; before that, in math mode only.
\,
¶Synonym: \thinspace
. Normally 3mu
, which is 1/6em.
Can be used in both math mode and text mode (see \thinspace
& \negthinspace
).
This space is widely used, for instance between the function and the
infinitesimal in an integral \int f(x)\,dx
and, if an author does
this, before punctuation in a displayed equation.
The antiderivative is \begin{equation} 3x^{-1/2}+3^{1/2}\,. \end{equation}
\!
¶Synonym: \negthinspace
. A negative thin space. Normally
-3mu
. With the amsmath
package, or as of the 2020-10-01
LaTeX release, can be used in text mode as well as math mode;
otherwise, the \!
command is math mode only but the
\negthinspace
command has always also worked in text mode
(see \thinspace
& \negthinspace
).
\quad
¶This is 18mu, that is, 1em. This is often used for space
surrounding equations or expressions, for instance for the space between
two equations inside a displaymath
environment. It is available
in both text and math mode.
\qquad
¶A length of 2 quads, that is, 36mu = 2em. It is available in both text and math mode.
\smash
¶Synopsis:
\smash{subformula}
Typeset subformula as if its height and depth were zero.
In this example the exponential is so tall that without the
\smash
command LaTeX would separate its line from the line
above it, and the uneven line spacing might be unsightly.
To compute the tetration $\smash{2^{2^{2^2}}}$, evaluate from the top down, as $2^{2^4}=2^{16}=65536$.
(Because of the \smash
the printed expression could run into the
line above so you may want to wait until the final version of the
document to make such adjustments.)
This pictures the effect of \smash
by using \fbox
to
surround the box that LaTeX will put on the line. The
\blackbar
command makes a bar extending from 10 points below
the baseline to 20 points above.
\newcommand{\blackbar}{\rule[-10pt]{5pt}{30pt}} \fbox{\blackbar} \fbox{\smash{\blackbar}}
The first box that LaTeX places is 20 points high and 10 points deep. But the second box is treated by LaTeX as having zero height and zero depth, despite that the ink printed on the page still extends well above and below the line.
The \smash
command appears often in mathematics to adjust the
size of an element that surrounds a subformula. Here the first radical
extends below the baseline while the second lies just on the baseline.
\begin{equation} \sqrt{\sum_{0\leq k< n} f(k)} \sqrt{\vphantom{\sum}\smash{\sum_{0\leq k< n}} f(k)} \end{equation}
Note the use of \vphantom
to give the \sqrt
command an
argument with the height of the \sum
(see \phantom
& \vphantom
& \hphantom
).
While most often used in mathematics, the \smash
command can
appear in other contexts. However, it doesn’t change into horizontal
mode. So if it starts a paragraph then you should first put a
\leavevmode
, as in the bottom line below.
Text above. \smash{smashed, no indent} % no paragraph indent \leavevmode\smash{smashed, with indent} % usual paragraph indent
The package mathtools
has operators that provide even finer
control over smashing a subformula box.
\phantom
& \vphantom
& \hphantom
¶Synopsis:
\phantom{subformula}
or
\vphantom{subformula}
or
\hphantom{subformula}
The \phantom
command creates a box with the same height, depth,
and width as subformula, but empty. That is, this command causes
LaTeX to typeset the space but not fill it with the material. Here
LaTeX will put a blank line that is the correct width for the answer,
but will not show that answer.
\begin{displaymath} \int x^2\,dx=\mbox{\underline{$\phantom{(1/3)x^3+C}$}} \end{displaymath}
The \vphantom
variant produces an invisible box with the same
vertical size as subformula, the same height and depth, but having
zero width. And \hphantom
makes a box with the same width as
subformula but with zero height and depth.
In this example, the tower of exponents in the second summand expression
is so tall that TeX places this expression further down than its
default. Without adjustment, the two summand expressions would be at
different levels. The \vphantom
in the first expression tells
TeX to leave as much vertical room as it does for the tower, so the
two expressions come out at the same level.
\begin{displaymath} \sum_{j\in\{0,\ldots\, 10\}\vphantom{3^{3^{3^j}}}} \sum_{i\in\{0,\ldots\, 3^{3^{3^j}}\}} i\cdot j \end{displaymath}
These commands are often used in conjunction with \smash
.
See \smash
, which includes another example of \vphantom
.
The three phantom commands appear often but note that LaTeX provides
a suite of other commands to work with box sizes that may be more
convenient, including \makebox
(see \mbox
& \makebox
) as well
as \settodepth
(see \settodepth
), \settoheight
(see \settoheight
), and \settowidth
(see \settowidth
).
In addition, the mathtools
package has many commands that offer
fine-grained control over spacing.
All three commands produce an ordinary box, without any special
mathematics status. So to do something like attaching a superscript you
should give it such a status, for example with the \operatorname
command from the package amsmath
.
While most often used in mathematics, these three can appear in other
contexts. However, they don’t cause LaTeX to change into horizontal
mode. So if one of these starts a paragraph then you should prefix it
with \leavevmode
.
\mathstrut
¶Synopsis:
\mathstrut
The analogue of \strut
for mathematics. See \strut
.
The input $\sqrt{x} + \sqrt{x^i}$
gives output where the
second radical is taller than the first. To add extra vertical space
without any horizontal space, so that the two have the same height, use
$\sqrt{x\mathstrut} + \sqrt{x^i\mathstrut}$
.
The \mathstrut
command adds the vertical height of an open
parenthesis, (
, but no horizontal space. It is defined as
\vphantom{(}
, so see \phantom
& \vphantom
& \hphantom
for
more. An advantage over \strut
is that \mathstrut
adds no
depth, which is often the right thing for formulas. Using the height of
an open parenthesis is just a convention; for complete control over the
amount of space, use \rule
with a width of zero. See \rule
.
TeX’s rules for typesetting a formula depend on the context. For
example, inside a displayed equation, the input \sum_{0\leq
i<n}k^m=\frac{n^{m+1}}{m+1}+\mbox{lower order terms}
will give
output with the summation index centered below the summation symbol.
But if that input is inline then the summation index is off to the right
rather than below, so it won’t push the lines apart. Similarly, in a
displayed context, the symbols in the numerator and denominator will be
larger than for an inline context, and in display math subscripts and
superscripts are further apart then they are in inline math.
TeX uses four math styles.
\begin{equation} ... \end{equation}
.
TeX determines a default math style but you can override it with a
declaration of \displaystyle
, or \textstyle
, or
\scriptstyle
, or \scriptscriptstyle
.
In this example, the ‘Arithmetic’ line’s fraction will look scrunched.
\begin{tabular}{r|cc} \textsc{Name} &\textsc{Series} &\textsc{Sum} \\ \hline Arithmetic &$a+(a+b)+(a+2b)+\cdots+(a+(n-1)b)$ &$na+(n-1)n\cdot\frac{b}{2}$ \\ Geometric &$a+ab+ab^2+\cdots+ab^{n-1}$ &$\displaystyle a\cdot\frac{1-b^n}{1-b}$ \\ \end{tabular}
But because of the \displaystyle
declaration,
the ‘Geometric’ line’s fraction will be easy to read, with
characters the same size as in the rest of the line.
Another example is that, compared to the same input without the declaration, the result of
we get $\pi=2\cdot{\displaystyle\int_{x=0}^1 \sqrt{1-x^2}\,dx}$
will have an integral sign that is much taller. Note that here the
\displaystyle
applies to only part of the formula, and it is
delimited by being inside curly braces, as ‘{\displaystyle ...}’.
The last example is a continued fraction.
\begin{equation} a_0+\frac{1}{ \displaystyle a_1+\frac{\mathstrut 1}{ \displaystyle a_2+\frac{\mathstrut 1}{ \displaystyle a_3}}} \end{equation}
Without the \displaystyle
declarations, the denominators would be
set in script style and scriptscript style. (The \mathstrut
improves the height of the denominators; see \mathstrut
.)
LaTeX contains a wide variety of mathematics facilities. Here are some that don’t fit into other categories.
:
& \colon
¶Synopsis, one of:
: \colon
In mathematics, the colon character, :
, is a relation.
With side ratios \( 3:4 \) and \( 4:5 \), the triangle is right.
Ordinary LaTeX defines \colon
to produce the colon character
with the spacing appropriate for punctuation, as in set-builder notation
\{x\colon 0\leq x<1\}
.
But the widely-used amsmath
package defines \colon
for use
in the definition of functions f\colon D\to C
. So if you want
the colon character as a punctuation then use \mathpunct{:}
.
\*
¶Synopsis:
\*
A multiplication symbol that allows a line break. If there is a break
then LaTeX puts a \times
symbol, ×, before
that break.
In \( A_1\* A_2\* A_3\* A_4 \)
, if there is no line break then
LaTeX outputs it as though it were \( A_1 A_2 A_3 A_4 \)
. If
a line break does happen, for example between the two middle ones, then
LaTeX sets it like \( A_1 A_2 \times \)
, followed by the
break, followed by \( A_3 A_4 \)
.
\frac
¶Synopsis:
\frac{numerator}{denominator}
Produces the fraction. Used as: \begin{displaymath}
\frac{1}{\sqrt{2\pi\sigma}} \end{displaymath}
. In inline math
mode it comes out small; see the discussion of \displaystyle
(see Math formulas).
\sqrt
¶Synopsis, one of:
\sqrt{arg} \sqrt[root-number]{arg}
The square root, or optionally other roots, of arg. The optional
argument root-number gives the root, i.e., enter the cube root of
x+y
as \sqrt[3]{x+y}
.
The size of the radical grows with that of arg (as the height of
the radical grows, the angle on the leftmost part gets steeper, until
for a tall enough arg
, it is vertical).
LaTeX has a separate \surd
symbol for making a square root
without arg (see Math symbols).
\stackrel
¶Synopsis:
\stackrel{text}{relation}
Put text above relation. To put a function name above an
arrow enter \stackrel{f}{\longrightarrow}
.
As LaTeX processes your document, at any point it is in one of six modes. They fall into three categories of two each, the horizontal modes, the math modes, and the vertical modes. Some commands only work in one mode or another (in particular, many commands only work in one of the math modes), and error messages will refer to these.
LR mode (for left-to-right mode; in plain TeX this is called
restricted horizontal mode) is in effect when LaTeX starts
making a box with an \mbox
command. As in paragraph mode,
LaTeX’s output is a string of words with spaces between them. Unlike
in paragraph mode, in LR mode LaTeX never starts a new line, it just
keeps going from left to right. (Although LaTeX will not complain
that the LR box is too long, when it is finished and next tries to put
that box into a line, it might well complain that the finished LR
box won’t fit there.)
Display math mode is when LaTeX is generating a displayed
mathematical formula. (Displayed formulas differ somewhat from inline
ones. One example is that the placement of the subscript on \int
differs in the two situations.)
Internal vertical mode is in effect when LaTeX starts making a
\vbox
. It has not such thing as page breaks, and as such is the
vertical analogue of LR mode.
For instance, if you begin a LaTeX article with ‘Let \( x \) be ...’ then these are the modes: first LaTeX starts every document in vertical mode, then it reads the ‘L’ and switches to paragraph mode, then the next switch happens at the ‘\(’ where LaTeX changes to math mode, and then when it leaves the formula it pops back to paragraph mode.
Paragraph mode has two subcases. If you use a \parbox
command
or a minipage
then LaTeX is put into paragraph mode. But it
will not put a page break here. Inside one of these boxes, called a
parbox, LaTeX is in inner paragraph mode. Its more usual
situation, where it can put page breaks, is outer paragraph mode
(see Page breaking).
\ensuremath
¶Synopsis:
\ensuremath{formula}
Ensure that formula is typeset in math mode.
For instance, you can redefine commands that ordinarily can be used only in math mode, so that they can be used both in math and in plain text.
\newcommand{\dx}{\ensuremath{dx}} In $\int f(x)\, \dx$, the \dx{} is an infinitesimal.
Caution: the \ensuremath
command is useful but not a panacea.
\newcommand{\alf}{\ensuremath{\alpha}} You get an alpha in text mode: \alf. But compare the correct spacing in $\alf+\alf$ with that in \alf+\alf.
Best is to typeset math things in a math mode.
The style of a page determines where LaTeX places the components of that page, such as headers and footers, and the text body. This includes pages in the main part of the document but also includes special pages such as the title page of a book, a page from an index, or the first page of an article.
The package fancyhdr
is commonly used for constructing page
styles. See its documentation.
\maketitle
¶Synopsis:
\maketitle
Generate a title. In the standard classes the title appears on a
separate page, except in the article
class where it is at the top
of the first page. (See Document class options, for information about
the titlepage
document class option.)
This example shows \maketitle
appearing in its usual place,
immediately after \begin{document}
.
\documentclass{article} \title{Constructing a Nuclear Reactor Using Only Coconuts} \author{Jonas Grumby\thanks{% With the support of a Ginger Grant from the Roy Hinkley Society.} \\ Skipper, \textit{Minnow} \and Willy Gilligan\thanks{% Thanks to the Mary Ann Summers foundation and to Thurston and Lovey Howell.} \\ Mate, \textit{Minnow} } \date{1964-Sep-26} \begin{document} \maketitle Just sit right back and you'll hear a tale, a tale of a fateful trip. That started from this tropic port, aboard this tiny ship. The mate was a mighty sailin' man, the Skipper brave and sure. Five passengers set sail that day for a three hour tour. A three hour tour. ...
You tell LaTeX the information used to produce the title by making
the following declarations. These must come before the
\maketitle
, either in the preamble or in the document body.
\author{name1 \and name2 \and ...}
¶Required. Declare the document author or authors. The argument is a
list of authors separated by \and
commands. To separate lines
within a single author’s entry, for instance to give the author’s
institution or address, use a double backslash, \\
. If you omit
the \author
declaration then you get ‘LaTeX Warning: No
\author given’.
\date{text}
¶Optional. Declare text to be the document’s date. The text
doesn’t need to be in a date format; it can be any text at all. If you
omit \date
then LaTeX uses the current date (see \today
).
To have no date, instead use \date{}
.
\thanks{text}
¶Optional. Produce a footnote. You can use it in the author information for acknowledgements as illustrated above, but you can also use it in the title, or anywhere that a footnote mark makes sense. It can be any text at all so you can use it for any purpose, such as to print an email address.
\title{text}
¶Required. Declare text to be the title of the document. Get line
breaks inside text with a double backslash, \\
. If you
omit the \title
declaration then the \maketitle
command
yields error ‘LaTeX Error: No \title given’.
To make your own title page, see titlepage
. You can either
create this as a one-off or you can include it as part of a renewed
\maketitle
command. Many publishers will provide a class to use
in place of article
that formats the title according to their
house requirements.
\pagenumbering
¶Synopsis:
\pagenumbering{number-style}
Specifies the style of page numbers, and resets the page number. The numbering style is reflected on the page, and also in the table of contents and other page references. This declaration has global scope so its effect is not stopped by an end of group such as a closing brace or an end of environment.
By default, LaTeX numbers pages starting at 1, using Arabic numerals.
The argument number-style is one of the following (see
also \alph \Alph \arabic \roman \Roman \fnsymbol
: Printing counters).
arabic
Arabic numerals: 1, 2, …
roman
lowercase Roman numerals: i, ii, …
Roman
uppercase Roman numerals: I, II, …
alph
lowercase letters: a, b, … If you have more than 26 pages then you get ‘LaTeX Error: Counter too large’.
Alph
uppercase letters: A, B, … If you have more than 26 pages then you get ‘LaTeX Error: Counter too large’.
gobble
no page number is output, though the number is still reset. References to that page also are blank.
This setting does not work with the popular package hyperref
,
so to omit page numbers you may want to instead use
\pagestyle{empty}
or \thispagestyle{empty}
.
If you want to typeset the page number in some other way, or change
where the page number appears on the page, see \pagestyle
(in short: use the fancyhdr
package). The list above of
LaTeX’s built-in numbering styles cannot be extended.
Traditionally, if a document has front matter—preface, table of
contents, etc.—then it is numbered with lowercase Roman
numerals. The main matter of a document uses arabic. LaTeX
implements this, by providing explicit commands for the different parts
(see \frontmatter
, \mainmatter
, \backmatter
).
As an explicit example, before the ‘Main’ section the pages are
numbered ‘a’, etc. Starting on the page containing the
\pagenumbering
call in that section, the pages are numbered
‘1’, etc.
\begin{document}\pagenumbering{alph} ... \section{Main}\pagenumbering{arabic} ...
If you want to change the value of the page number, then you
manipulate the page
counter (see Counters).
\pagestyle
¶Synopsis:
\pagestyle{style}
Declaration that specifies how the page headers and footers are typeset, from the current page onwards.
A discussion with an example is below. First, however: the package
fancyhdr
is now the standard way to manipulate headers and
footers. New documents that need to do anything other than one of the
standard options below should use this package. See its documentation
(https://ctan.org/pkg/fancyhdr).
Values for style:
plain
The header is empty. The footer contains only a page number, centered.
empty
The header and footer are both empty.
headings
Put running headers and footers on each page. The document style specifies what goes in there; see the discussion below.
myheadings
Custom headers, specified via the \markboth
or the
\markright
commands.
Some discussion of the motivation for LaTeX’s mechanism will help you
work with the options headings
or myheadings
. The
document source below produces an article, two-sided, with the pagestyle
headings
. On this document’s left hand pages, LaTeX wants (in
addition to the page number) the title of the current section. On its
right hand pages LaTeX wants the title of the current subsection.
When it makes up a page, LaTeX gets this information from the
commands \leftmark
and \rightmark
. So it is up to
\section
and \subsection
to store that information there.
\documentclass[twoside]{article} \pagestyle{headings} \begin{document} ... \section{Section 1} ... \subsection{Subsection 1.1} ... \section{Section 2} ... \subsection{Subsection 2.1} ... \subsection{Subsection 2.2} ...
Suppose that the second section falls on a left page. Although when the page starts it is in the first section, LaTeX will put ‘Section 2’ in the left page header. As to the right header, if no subsection starts before the end of the right page then LaTeX blanks the right hand header. If a subsection does appear before the right page finishes then there are two cases. If at least one subsection starts on the right hand page then LaTeX will put in the right header the title of the first subsection starting on that right page. If at least one of 2.1, 2.2, …, starts on the left page but none starts on the right then LaTeX puts in the right hand header the title of the last subsection to start, that is, the one in effect during the right hand page.
To accomplish this, in a two-sided article, LaTeX has \section
issue a command \markboth
, setting \leftmark
to
‘Section 2’ and setting \rightmark
to an empty content.
And, LaTeX has \subsection
issue a command \markright
,
setting \rightmark
to ‘Subsection 2.1’, etc.
Here are the descriptions of \markboth
and \markright
:
\markboth{left-head}{right-head}
¶Sets both the right hand and left hand heading information for either a
page style of headings
or myheadings
. A left hand page
heading left-head is generated by the last \markboth
command before the end of the page. A right hand page heading
right-head is generated by the first \markboth
or
\markright
that comes on the page if there is one, otherwise by
the last one that came before that page.
\markright{right-head}
¶Sets the right hand page heading, leaving the left unchanged.
\thispagestyle
¶Synopsis:
\thispagestyle{style}
Works in the same way as the \pagestyle
(see \pagestyle
),
except that it changes to style for the current page only. This
declaration has global scope, so its effect is not delimited by braces
or environments.
Often the first page of a chapter or section has a different style. For
example, this LaTeX book document has the first page of the first
chapter in plain
style, as is the default (see Page styles).
\documentclass{book} \pagestyle{headings} \begin{document} \chapter{First chapter} ... \chapter{Second chapter}\thispagestyle{empty} ...
The plain
style has a page number on it, centered in the footer.
To make the page entirely empty, the command
\thispagestyle{empty}
immediately follows the second
\chapter
.
\thepage
¶If you want to change the appearance of page numbers only in the page
headers, for example by adding an ornament, typesetting in small caps,
etc., then the fancyhdr
package, as mentioned in a previous
section, is the best approach.
On the other hand, you may want to change how page numbers are denoted
everywhere, including the table of contents and cross-references, as
well as the page headers. In this case, you should redefine
\thepage
, which is the command LaTeX uses for the
representation of page numbers.
However, \thepage
should do any typesetting or other
complicated maneuvers, but merely expand to the intended page number
representation. The results of a complicated redefinition of
\thepage
are not predictable, but LaTeX’s report of page
numbers in diagnostic messages, at least, will become unusable.
There is some discussion of this issue at https://tex.stackexchange.com/questions/687258.
LaTeX has many ways to produce white space, or filled space. Some of these are best suited to mathematical text; for these see Spacing in math mode.
\enspace
& \quad
& \qquad
\hspace
\hfill
\hss
\spacefactor
\
~
, \nobreakspace
\thinspace
& \negthinspace
\/
\hrulefill
& \dotfill
\bigskip
& \medskip
& \smallskip
\bigbreak
& \medbreak
& \smallbreak
\strut
\vspace
\vfill
\addvspace
\enspace
& \quad
& \qquad
¶Synopsis, one of:
\enspace \quad \qquad
Insert a horizontal space of 1/2em, 1em, or 2em. The em is a length defined by a font designer, often thought of as being the width of a capital M. One advantage of describing space in ems is that it can be more portable across documents than an absolute measurement such as points (see Lengths/em).
This puts a suitable gap between two graphics.
\begin{center} \includegraphics{womensmile.png}% \qquad\includegraphics{mensmile.png} \end{center}
See Spacing in math mode, for \quad
and \qquad
. These
are lengths from centuries of typesetting and so may be a better choice
in many circumstances than arbitrary lengths, such as you get with
\hspace
.
\hspace
¶Synopsis, one of:
\hspace{length} \hspace*{length}
Insert the amount length of horizontal space. The length can
be positive, negative, or zero; adding a negative amount of space is
like backspacing. It is a rubber length, that is, it may contain a
plus
or minus
component, or both (see Lengths).
Because the space is stretchable and shrinkable, it is sometimes called
glue.
This makes a line with ‘Name:’ an inch from the right margin.
\noindent\makebox[\linewidth][r]{Name:\hspace{1in}}
The *
-form inserts horizontal space that is non-discardable. More
precisely, when TeX breaks a paragraph into lines any white
space—glues and kerns—that come at a line break are discarded. The
*
-form avoids that (technically, it adds a non-discardable
invisible item in front of the space).
In this example
\parbox{0.8\linewidth}{% Fill in each blank: Four \hspace*{1in} and seven years ago our fathers brought forth on this continent, a new \hspace*{1in}, conceived in \hspace*{1in}, and dedicated to the proposition that all men are created \hspace*{1in}.}
the 1 inch blank following ‘conceived in’ falls at the start
of a line. If you erase the *
then LaTeX discards the blank.
Here, the \hspace
separates the three graphics.
\begin{center} \includegraphics{lion.png}% comment keeps out extra space \hspace{1cm minus 0.25cm}\includegraphics{tiger.png}% \hspace{1cm minus 0.25cm}\includegraphics{bear.png} \end{center}
Because the argument to each \hspace
has minus 0.25cm
,
each can shrink a little if the three figures are too wide. But each
space won’t shrink more than 0.25cm (see Lengths).
\hfill
¶Synopsis:
\hfill
Produce a rubber length which has no natural space but that can stretch horizontally as far as needed (see Lengths).
This creates a one-line paragraph with ‘Name:’ on the left side of the page and ‘Quiz One’ on the right.
\noindent Name:\hfill Quiz One
The \hfill
command is equivalent to \hspace{\fill}
and
so the space can be discarded at line breaks. To avoid that instead use
\hspace*{\fill}
(see \hspace
).
Here the graphs are evenly spaced in the middle of the figure.
\newcommand*{\vcenteredhbox}[1]{\begin{tabular}{@{}c@{}}#1\end{tabular}} ... \begin{figure} \hspace*{\fill}% \vcenteredhbox{\includegraphics{graph0.png}}% \hfill\vcenteredhbox{\includegraphics{graph1.png}}% \hspace*{\fill}% \caption{Comparison of two graphs} \label{fig:twographs} \end{figure}
Note the \hspace*
’s where the space could otherwise be dropped.
\hss
¶Synopsis:
\hss
Produce a horizontal space that is infinitely shrinkable as well as
infinitely stretchable (this command is a TeX primitive). LaTeX
authors should reach first for the \makebox
command to get the
effects of \hss
(see \mbox
& \makebox
).
Here, the first line’s \hss
makes the Z stick out to the right,
overwriting the Y. In the second line the Z sticks out to the left,
overwriting the X.
X\hbox to 0pt{Z\hss}Y X\hbox to 0pt{\hss Z}Y
Without the \hss
you get something like ‘Overfull \hbox
(6.11111pt too wide) detected at line 20’.
\spacefactor
¶Synopsis:
\spacefactor=integer
Influence LaTeX’s stretching and shrinking of glue. Few user-level documents need to use this.
While LaTeX is laying out the material, it may stretch or shrink the
gaps between words. (This space is not a character; it is called the
interword glue; see \hspace
). The \spacefactor
parameter
(a TeX primitive) allows you to, for instance, have the space
after a period stretch more than the space after a word-ending letter.
After LaTeX places each character, or rule or other box, it sets a parameter called the space factor. If the next thing in the input is a space then this parameter affects how much stretching or shrinking can happen. A space factor that is larger than the normal value means that the glue can stretch more and shrink less. Normally, the space factor is 1000. This value is in effect following most characters, and any non-character box or math formula. But it is 3000 after a period, exclamation mark, or question mark, 2000 after a colon, 1500 after a semicolon, 1250 after a comma, and 0 after a right parenthesis or bracket, or closing double quote or single quote. Finally, it is 999 after a capital letter.
If the space factor f is 1000 then the glue gap will be the font’s normal space value (for Computer Modern Roman 10 point this is 3.3333pt). Otherwise, if the space factor f is greater than 2000 then TeX adds the font’s extra space value (for Computer Modern Roman 10 point this is 1.11111pt), and then the font’s normal stretch value is multiplied by f /1000 and the normal shrink value is multiplied by 1000/f (for Computer Modern Roman 10 point these are 1.66666 and 1.11111pt).
For example, consider the period ending ‘A man's best friend is
his dog.’. After it, TeX puts in a fixed extra space, and also
allows the glue to stretch 3 times as much and shrink 1/3 as much, as
the glue after friend
or any of the other words, since they are
not followed by punctuation.
The rules for space factors are even more complex because they play
additional roles. In practice, there are two consequences. First, if
a period or other punctuation is followed by a right parenthesis or
bracket, or right single or double quote then the spacing effect of
that period carries through those characters (that is, the following
glue will have increased stretch and shrink). Second, if punctuation
comes after a capital letter then the normal effect of the period is
does not happen, so you get an ordinary space. This second case also
affects abbreviations that do not end in a capital letter
(see \@
).
You can only use \spacefactor
in paragraph mode or LR mode
(see Modes). You can see the current value with
\the\spacefactor
or \showthe\spacefactor
.
Finally, not especially related to \spacefactor
itself: if you
get errors like ‘You can't use `\spacefactor' in vertical mode’,
or ‘You can't use `\spacefactor' in math mode.’, or
‘Improper \spacefactor’ then you have probably tried to redefine
an internal command. See \makeatletter
& \makeatother
.
\@
¶Synopsis:
capital-letter\@.
Treat a period (or other punctuation) as sentence-ending, where LaTeX would otherwise think it is part of an abbreviation. LaTeX thinks that a period ends an abbreviation if the period comes after a capital letter, and otherwise thinks the period ends the sentence.
This example shows the two cases to remember.
The songs \textit{Red Guitar}, etc.\ are by Loudon Wainwright~III\@.
The first period ends the abbreviation ‘etc.’ but not the
sentence. The backslash-space, \
, produces a mid-sentence
space. The second period ends the sentence, despite it being preceded
by a capital letter. We tell LaTeX that it ends the sentence by
putting \@
before it.
So: if you have a capital letter followed by a period that ends the
sentence, then put \@
before the period. This holds even if
there is an intervening right parenthesis or bracket, or right single or
double quote, because the spacing effect of that period carries through
those characters. For example, this
Use the \textit{Instructional Practices Guide}, (a book by the MAA)\@.
will have correct inter-sentence spacing after the period.
The \@
command is only for text modes. If you use it outside
of a text mode then you get the error ‘You can't use
`\spacefactor' in vertical mode’ (see Modes).
All the above applies equally to question marks and exclamation points
as periods, since all are sentence-ending punctuation, and LaTeX
increases the space after each in the same way, when they end a
sentence. LaTeX also increases spacing after colon, semicolon, and
comma characters (see \spacefactor
).
In addition: the converse case is a period (or other punctuation) that
does not end a sentence. For that case, follow the period with a
backslash-space, (\
), or a tie, (~
), or \@
.
Examples are Nat.\ Acad.\ Science
, and Mr.~Bean
, and
(manure, etc.\@) for sale
(note in the last one that the
\@
comes after the period but before the closing parenthesis).
\frenchspacing
& \nonfrenchspacing
¶Synopsis, one of:
\frenchspacing \nonfrenchspacing
\frenchspacing
causes LaTeX to make spacing after all
punctuation, including periods, be the same as the space between words
in the middle of a sentence. \nonfrenchspacing
switches back
to the default handling in which spacing after most punctuation stretches
or shrinks differently than a word space (see \spacefactor
).
In American English, the typesetting tradition is to adjust, typically
increasing, the space after punctuation more than the space between
words that are in the middle of a sentence. Declaring
\frenchspacing
(the command is inherited from plain TeX)
switches to the tradition that all spaces are treated equally.
If your LaTeX document specifies the language being used, for
example with the babel
package, the necessary settings
should be taken care of for you.
\normalsfcodes
¶Synopsis:
\normalsfcodes
Reset the LaTeX space factors to the default values
(see \spacefactor
).
\
¶This section refers to the command consisting of two characters, a backslash followed by a space. Synopsis:
\
Produce a space. By default it produces white space of length 3.33333pt plus 1.66666pt minus 1.11111pt.
When you type one or more blanks between words, LaTeX produces whitespace that is different than an explicit space. This illustrates:
\begin{tabular}{rl} One blank:& makes some space \\ Three blanks:& in a row \\ Three spaces:&\ \ \ in a row \\ \end{tabular}
On the first line LaTeX puts some space after the colon. On the
second line LaTeX collapses the three blanks to output one
whitespace, so you end with the same space after the colon as in the
first line. LaTeX would similarly collapse them to a single
whitespace if one, two or all of the three blanks were replaced by a
tab, or by a newline. However, the bottom line asks for three spaces so
the white area is wider. That is, the backslash-space command creates a
fixed amount of horizontal space. (Note that you can define a
horizontal space of any width at all with \hspace
;
see \hspace
.)
The backslash-space command has two main uses. It is often used after
control sequences to keep them from gobbling the blank that follows, as
after \TeX
in \TeX\ (or \LaTeX)
. (But using curly braces
has the advantage of still working whether the next character is a blank
or any other non-letter, as in \TeX{} (or \LaTeX{})
in which
{}
can be added after \LaTeX
as well as after
\TeX
.) The other common use is that it marks a period as ending
an abbreviation instead of ending a sentence, as in Prof.\ Smith
or Jones et al.\ (1993)
(see \@
).
Under normal circumstances, \
TAB and \
NEWLINE
are equivalent to backslash-space, \
.
In order to allow source code indentation, under normal circumstances, TeX ignores leading blanks in a line. So the following prints ‘one word’:
one word
where the white space between ‘one’ and ‘word’ is produced by the newline after ‘one’, not by the space before ‘word’.
~
, \nobreakspace
¶Synopsis:
before~after
The tie character, ~
, produces a space between before and
after at which the line will not be broken. By default the white
space has length 3.33333pt plus 1.66666pt minus
1.11111pt (see Lengths). The command \nobreakspace
and the Unicode input character U+00A0 (also in many 8-bit encodings)
are synonyms.
Note that the word ‘tie’ has this meaning in the TeX/Texinfo community; this differs from the typographic term “tie”, which is a diacritic in the shape of an arc, called a “tie-after” accent in The TeXbook.
Here LaTeX will not break the line between the final two words:
Thanks to Prof.~Lerman.
In addition, despite the period, LaTeX does not use the
end-of-sentence spacing (see \@
).
Ties prevent a line break where that could cause confusion. They also
still allow hyphenation (of either of the tied words), so they are
generally preferable to putting consecutive words in an \mbox
(see \mbox
& \makebox
).
Exactly where ties should be used is something of a matter of taste, sometimes alarmingly dogmatic taste, among readers. Nevertheless, here are some usage models, many of them from The TeXbook.
Chapter~12
, or Theorem~\ref{th:Wilsons}
, or
Figure~\ref{fig:KGraph}
.
(b)~Show that $f(x)$ is
(1)~continuous, and (2)~bounded
.
$745.7.8$~watts
(the
siunitx
package has a special facility for this) or
144~eggs
. This includes between a month and day number in a date:
October~12
or 12~Oct
. In general, in any expressions where
numbers and abbreviations or symbols are separated by a space:
AD~565
, or 2:50~pm
, or Boeing~747
, or
268~Plains Road
, or \$$1.4$~billion
. Other common
choices here are a thin space (see \thinspace
& \negthinspace
) and
no space at all.
equals~$n$
, or
less than~$\epsilon$
, or given~$X$
, or modulo~$p^e$
for all large~$n$
(but compare is~$15$
with is $15$~times
the height
). Between mathematical symbols in apposition with nouns:
dimension~$d$
or function~$f(x)$
(but compare with
length $l$~or more
). When a symbol is a tightly bound object of a
preposition: of~$x$
, or from $0$ to~$1$
, or in
common with~$m$
.
$1$,~$2$, or~$3$
or $1$,~$2$,
\ldots,~$n$
.
Donald~E. Knuth
, or Luis~I. Trabb~Pardo
, or
Charles~XII
—but you must give TeX places to break the line
so you might do Charles Louis Xavier~Joseph de~la
Vall\'ee~Poussin
.
\thinspace
& \negthinspace
¶Synopsis, one of:
\thinspace \negthinspace
These produce unbreakable and unstretchable spaces of 1/6em and
-1/6em, respectively. These are the text mode equivalents of
\,
and \!
(see Spacing in math mode/\thinspace).
You can use \,
as a synonym for \thinspace
in text mode.
One common use of \thinspace
is as the space between nested
quotes:
Killick replied, ``I heard the Captain say, `Ahoy there.'\thinspace''
Another use is that some style guides call for a \thinspace
between an ellipsis and a sentence ending period (other sty