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  <title>&latex;2e reference manual 2.0</title>
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<!-- xx merge http://ctan.org/tex-archive/info/latex-info/ -->
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  <bookinfo>
    <legalnotice>
      <para>This document is version 2.0 (June 2008) of an
unofficial reference manual for &latex;, a document preparation
system.  &latex; is a macro package for &tex;.</para>
      <para>This was originally translated from <filename>LATEX.HLP</filename> v1.0a in the VMS
Help Library.  The pre-translation version was written by
George&#xa0;D. Greenwade of Sam Houston State University.  The
&latex;&#xa0;2.09 version was written by Stephen Gilmore.  The
&latex;2e version was adapted from this by Torsten Martinsen.  Karl
Berry made further updates and additions, and gratefully acknowledges
using <citetitle>Hypertext Help with &latex;</citetitle>, by Sheldon Green, and the
<citetitle>&latex; Command Summary</citetitle> (for &latex; 2.09) by L.&#xa0;Botway
and C.&#xa0;Biemesderfer (published by the &tex; Users Group as
<citetitle>&tex;niques</citetitle> number 10), as reference material (text was not
directly copied).</para>
      <para>Copyright &copy; 2007, 2008 Karl Berry.
Copyright &copy; 1988, 1994, 2007 Stephen Gilmore.
Copyright &copy; 1994, 1995, 1996 Torsten Martinsen.</para>
      <para>Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.</para>
      <para>Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the entire
resulting derived work is distributed under the terms of a permission
notice identical to this one.</para>
      <para>Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions.</para>
    </legalnotice>
</bookinfo>
  <chapter label="" xreflabel="LaTeX2e" id="Top">
    <title>&latex;2e</title>
    <para>This document is version 2.0 (June 2008) of an
unofficial reference manual for &latex;, a document preparation
system.  It is intended to cover &latex;2e, which has been the
standard version of &latex; for many years.</para>
    <para><indexterm role="cp"><primary>Knuth, Donald E.</primary></indexterm><indexterm role="cp"><primary>Lamport, Leslie</primary></indexterm><indexterm role="cp"><primary>&latex; Project team</primary></indexterm>&latex; is implemented as a macro package for Donald&#xa0;E. Knuth's
&tex; typesetting program.  &latex; was originally created by Leslie
Lamport; it is now maintained by a group of volunteers
(<ulink url="http://latex-project.org">http://latex-project.org</ulink>).  The official documentation written
by the &latex; project is available there.  Again, the present
document is unofficial and has not been reviewed by the &latex;
maintainers.</para>
  </chapter>

  <chapter label="1" id="Overview">
    <title>Overview of &latex;</title>
    <para><indexterm role="cp"><primary>overview of &latex;</primary></indexterm><indexterm role="cp"><primary>&latex; overview</primary></indexterm>
The &latex; command typesets a file of text using the &tex; program
and the &latex; &ldquo;macro package&rdquo; for &tex;.  To be more specific,
it processes an input file containing the text of a document with
interspersed commands that describe how the text should be formatted.
It produces at least three files as output:</para>
    <orderedlist numeration="arabic">
      <listitem>
        <para>A main output file, which is one of:</para>
        <orderedlist numeration="arabic">
          <listitem>
            <para>If invoked as <command>latex</command>, a &ldquo;Device Independent&rdquo; (<filename>.dvi</filename>)
file. This contains commands that can be translated into commands for
a variety of output devices.  You can view such <filename>.dvi</filename> output of
&latex; by using a program such as <command>xdvi</command> (display directly)
or <command>dvips</command> (convert to PostScript).</para>
          </listitem>
          <listitem>
            <para>If invoked as <command>pdflatex</command>, a &ldquo;Portable Document Format&rdquo;
(<filename>.pdf</filename>) file.  Typically, this is a self-contained file, with
all fonts and images embedded.  This can be very useful, but it does
make the output much larger than the <filename>.dvi</filename> produced from the
same document.</para>
          </listitem>
        </orderedlist>
        <para>There are other less-common variants of &latex; (and &tex;) as well,
which can produce HTML, XML, and other things.</para>
      </listitem>
      <listitem>
        <para>A &ldquo;transcript&rdquo; or <filename>.log</filename> file that contains summary information and
diagnostic messages for any errors discovered in the input file.</para>
      </listitem>
      <listitem>
        <para>An &ldquo;auxiliary&rdquo; or <filename>.aux</filename> file. This is used by &latex; itself, for
things such as sectioning.</para>
      </listitem>
    </orderedlist>
    <para>A &latex; command begins with the command name, which consists of a
<literal>\</literal> followed by either (a)&#xa0;a string of letters or (b)&#xa0;a
single non-letter.  Arguments contained in square brackets, <literal>[]</literal>,
are optional while arguments contained in braces, <literal>{}</literal>, are
required.</para>
    <para>&latex; is case sensitive.  Enter all commands in lower case unless
explicitly directed to do otherwise.</para>
  </chapter>

  <chapter label="2" id="Starting-&-ending">
    <title>Starting &amp; ending</title>
    <para><indexterm role="cp"><primary>starting &amp; ending</primary></indexterm><indexterm role="cp"><primary>ending &amp; starting</primary></indexterm>
A minimal input file looks like the following:</para>
    <screen>
\documentclass{<replaceable>class</replaceable>}
\begin{document}
<replaceable>your text</replaceable>
\end{document}
</screen>
    <para role="continues">where the <replaceable>class</replaceable> is a valid document class for &latex;.
See <xref linkend="Document-classes"></xref>, for details of the various document classes
available locally.</para>
    <para><indexterm role="cp"><primary>preamble, defined</primary></indexterm>You may include other &latex; commands between the <literal>\documentclass</literal>
and the <literal>\begin{document}</literal> commands (this area is called the
<firstterm>preamble</firstterm>).</para>
  </chapter>

  <chapter label="3" id="Document-classes">
    <title>Document classes</title>
    <para><indexterm role="cp"><primary>document classes</primary></indexterm><indexterm role="cp"><primary>classes of documents</primary></indexterm><indexterm role="fn"><primary>\documentclass</primary></indexterm>
The class of a given document is defined with the command:</para>
    <screen>
\documentclass[<replaceable>options</replaceable>]{<replaceable>class</replaceable>}
</screen>
    <para role="continues">The <literal>\documentclass</literal> command must be the first command in a
&latex; source file.</para>
    <para><indexterm role="fn"><primary>article class</primary></indexterm><indexterm role="fn"><primary>report class</primary></indexterm><indexterm role="fn"><primary>book class</primary></indexterm><indexterm role="fn"><primary>letter class</primary></indexterm><indexterm role="fn"><primary>slides class</primary></indexterm>Built-in &latex; document <replaceable>class</replaceable> names are (many other document
classes are available as add-ons; see <xref linkend="Overview"></xref>):</para>
    <screen>
article  report  book  letter  slides
</screen>
<!-- xx briefly describe each one -->
    <para>Standard <replaceable>options</replaceable> are described below.</para>

    <sect1 label="3.1" id="Document-class-options">
      <title>Document class options</title>
      <para><indexterm role="cp"><primary>document class options</primary></indexterm><indexterm role="cp"><primary>options, document class</primary></indexterm><indexterm role="cp"><primary>class options</primary></indexterm><indexterm role="cp"><primary>global options</primary></indexterm>
You can specify so-called <firstterm>global options</firstterm> or <firstterm>class options</firstterm>
to the <literal>\documentclass</literal> command by enclosing them in square
brackets as usual.  To specify more than one <replaceable>option</replaceable>, separate
them with a comma:</para>
      <screen>
\documentclass[<replaceable>option1</replaceable>,<replaceable>option2</replaceable>,...]{<replaceable>class</replaceable>}
</screen>
      <para>Here is the list of the standard class options.</para>
      <para><indexterm role="fn"><primary>10pt option</primary></indexterm><indexterm role="fn"><primary>11pt option</primary></indexterm><indexterm role="fn"><primary>12pt option</primary></indexterm>All of the standard classes except <literal>slides</literal> accept the following
options for selecting the typeface size (default is <literal>10pt</literal>):</para>
      <screen>
10pt  11pt  12pt
</screen>
      <para><indexterm role="fn"><primary>a4paper option</primary></indexterm><indexterm role="fn"><primary>a5paper option</primary></indexterm><indexterm role="fn"><primary>b5paper option</primary></indexterm><indexterm role="fn"><primary>executivepaper option</primary></indexterm><indexterm role="fn"><primary>legalpaper option</primary></indexterm><indexterm role="fn"><primary>letterpaper option</primary></indexterm>All of the standard classes accept these options for selecting the paper
size (default is <literal>letterpaper</literal>):</para>
      <screen>
a4paper a5paper b5paper executivepaper legalpaper letterpaper
</screen>
      <para><indexterm role="fn"><primary>draft option</primary></indexterm><indexterm role="fn"><primary>final option</primary></indexterm><indexterm role="fn"><primary>fleqn option</primary></indexterm><indexterm role="fn"><primary>landscape option</primary></indexterm><indexterm role="fn"><primary>leqno option</primary></indexterm><indexterm role="fn"><primary>openbib option</primary></indexterm><indexterm role="fn"><primary>titlepage option</primary></indexterm><indexterm role="fn"><primary>notitlepage option</primary></indexterm>Miscellaneous other options:</para>
      <variablelist>
        <varlistentry>
          <term><literal>draft, final</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>black boxes, omitting</primary></indexterm>mark/do not mark overfull boxes with a big black box; default is <literal>final</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>fleqn</literal></term>
          <listitem>
            <para>Put displayed formulas flush left; default is centered.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>landscape</literal></term>
          <listitem>
            <para>Selects landscape format; default is portrait.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>leqno</literal></term>
          <listitem>
            <para>Put equation numbers on the left side of equations; default is the right side.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>openbib</literal></term>
          <listitem>
            <para>Use &ldquo;open&rdquo; bibliography format.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>titlepage, notitlepage</literal></term>
          <listitem>
            <para>Specifies whether the title page is separate; default depends on the class.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>These options are not available with the slides class:</para>
      <para><indexterm role="fn"><primary>onecolumn option</primary></indexterm><indexterm role="fn"><primary>twocolumn option</primary></indexterm><indexterm role="fn"><primary>oneside option</primary></indexterm><indexterm role="fn"><primary>twoside option</primary></indexterm><indexterm role="fn"><primary>openright option</primary></indexterm><indexterm role="fn"><primary>openany option</primary></indexterm></para>
      <variablelist>
        <varlistentry>
          <term><literal>onecolumn</literal></term>
          <term><literal>twocolumn</literal></term>
          <listitem>
            <para>Typeset in one or two columns; default is <literal>onecolumn</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>oneside</literal></term>
          <term><literal>twoside</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\evensidemargin</primary></indexterm><indexterm role="fn"><primary>\oddsidemargin</primary></indexterm>Selects one- or two-sided layout; default is <literal>oneside</literal>, except
for the <literal>book</literal> class.</para>
            <para>The <literal>\evensidemargin</literal> (<literal>\oddsidemargin</literal> parameter determines
the distance on even (odd) numbered pages between the left side of the
page and the text's left margin.  The defaults vary with the paper
size and whether one- or two-side layout is selected.  For one-sided
printing the text is centered, for two-sided, <literal>\oddsidemargin</literal> is
40% of the difference between <literal>\paperwidth</literal> and <literal>\textwidth</literal>
with <literal>\evensidemargin</literal> the remainder.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>openright</literal></term>
          <term><literal>openany</literal></term>
          <listitem>
            <para>Determines if a chapter should start on a
right-hand page; default is <literal>openright</literal> for book.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>The <literal>slides</literal> class offers the option <literal>clock</literal> for printing
the time at the bottom of each note.</para>
      <para><indexterm role="cp"><primary>packages, loading</primary></indexterm><indexterm role="cp"><primary>loading additional packages</primary></indexterm><indexterm role="fn"><primary>\usepackage</primary></indexterm>Additional packages are loaded like this:</para>
      <screen>
\usepackage[<replaceable>options</replaceable>]{<replaceable>pkg</replaceable>}
</screen>
      <para>To specify more than one <replaceable>pkg</replaceable>, you can separate them with a
comma, or use multiple <literal>\usepackage</literal> commands.</para>
      <para><indexterm role="cp"><primary>global options</primary></indexterm><indexterm role="cp"><primary>options, global</primary></indexterm>Any options given in the <literal>\documentclass</literal> command that are unknown
by the selected document class are passed on to the packages loaded with
<literal>\usepackage</literal>.</para>
    </sect1>
  </chapter>

  <chapter label="4" id="Typefaces">
    <title>Typefaces</title>
    <para><indexterm role="cp"><primary>typefaces</primary></indexterm><indexterm role="cp"><primary>fonts</primary></indexterm>
Two important aspects of selecting a <firstterm>font</firstterm> are specifying a size
and a style.  The &latex; commands for doing this are described here.</para>

    <sect1 label="4.1" id="Font-styles">
      <title>Font styles</title>
      <para><indexterm role="cp"><primary>font styles</primary></indexterm><indexterm role="cp"><primary>typeface styles</primary></indexterm><indexterm role="cp"><primary>styles of text</primary></indexterm>
The following type style commands are supported by &latex;.</para>
      <para>These commands are used like <literal>\textit{italic text}</literal>. The
corresponding command in parenthesis is the &ldquo;declaration form&rdquo;, which
takes no arguments. The scope of the declaration form lasts until the
next type style command or the end of the current group.</para>
      <para>The declaration forms are cumulative; i.e., you can say either
<literal>\sffamily\bfseries</literal> or <literal>\bfseries\sffamily</literal> to get bold
sans serif.</para>
      <para>You can also use the environment form of the declaration forms; for instance,
<literal>\begin{ttfamily}...\end{ttfamily}</literal>.</para>
      <variablelist>
        <varlistentry>
          <term><literal>\textrm (\rmfamily)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textrm</primary></indexterm><indexterm role="fn"><primary>\rmfamily</primary></indexterm>Roman.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textit (\itshape)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textit</primary></indexterm><indexterm role="fn"><primary>\itshape</primary></indexterm>Italics.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\emph</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\emph</primary></indexterm><indexterm role="cp"><primary>emphasis</primary></indexterm>Emphasis (switches between <literal>\textit</literal> and <literal>\textrm</literal>).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textmd (\mdseries)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textmd</primary></indexterm><indexterm role="fn"><primary>\mdseries</primary></indexterm>Medium weight (default).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textbf (\bfseries)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textbf</primary></indexterm><indexterm role="fn"><primary>\bfseries</primary></indexterm>Boldface.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textup (\upshape)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textup</primary></indexterm><indexterm role="fn"><primary>\upshape</primary></indexterm>Upright (default). The opposite of slanted.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textsl (\slshape)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textsl</primary></indexterm><indexterm role="fn"><primary>\slshape</primary></indexterm>Slanted.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textsf (\sffamily)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textsf</primary></indexterm><indexterm role="fn"><primary>\sffamily</primary></indexterm>Sans serif.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textsc (\scshape)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textsc</primary></indexterm><indexterm role="fn"><primary>\scshape</primary></indexterm>Small caps.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\texttt (\ttfamily)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\texttt</primary></indexterm><indexterm role="fn"><primary>\ttfamily</primary></indexterm>Typewriter.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textnormal (\normalfont)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\textnormal</primary></indexterm><indexterm role="fn"><primary>\normalfont</primary></indexterm>Main document font.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\mathrm</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\mathrm</primary></indexterm>Roman, for use in math mode.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\mathbf</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\mathbf</primary></indexterm>Boldface, for use in math mode.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\mathsf</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\mathsf</primary></indexterm>Sans serif, for use in math mode.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\mathtt</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\mathtt</primary></indexterm>Typewriter, for use in math mode.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\mathit</literal></term>
          <term><literal>(\mit)</literal></term>
          <listitem>
            <para>Italics, for use in math mode.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\mathnormal</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\mathnormal</primary></indexterm>For use in math mode, e.g. inside another type style declaration.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\mathcal</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\mathcal</primary></indexterm>`Calligraphic' letters, for use in math mode.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>In addition, the command
<literal>\mathversion{bold}</literal>
<indexterm role="fn"><primary>\mathversion</primary></indexterm>can be used for switching to bold letters and symbols in
formulas. <literal>\mathversion{normal}</literal> restores the default.</para>
      <para>&latex; also provides these commands, which unconditionally switch to
the given style, that is, are <emphasis>not</emphasis> cumulative.  They are used
differently than the above commands, too: <literal>{\<replaceable>cmd</replaceable> ...}</literal>
instead of <literal>\<replaceable>cmd</replaceable>{...}</literal>.  These are two very different
things.</para>
      <variablelist>
        <varlistentry>
          <term><literal>\bf</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>bold font</primary></indexterm>Switch to <emphasis role="bold">bold face</emphasis>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\cal</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>script letters for math</primary></indexterm><indexterm role="cp"><primary>calligraphic letters for math</primary></indexterm>Switch to calligraphic letters for math.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\em</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>emphasis</primary></indexterm>Emphasis (italics within roman, roman within italics).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\it</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>italic font</primary></indexterm>Italics.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\rm</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>roman font</primary></indexterm>Roman.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\sc</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>small caps font</primary></indexterm>Small caps.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\sf</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>sans serif font</primary></indexterm>Sans serif.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\sl</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>slanted font</primary></indexterm><indexterm role="cp"><primary>oblique font</primary></indexterm>Slanted (oblique).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\tt</literal></term>
          <listitem>
            <para><indexterm role="cp"><primary>typewriter font</primary></indexterm><indexterm role="cp"><primary>monospace font</primary></indexterm><indexterm role="cp"><primary>fixed-width font</primary></indexterm>Typewriter (monospace, fixed-width).</para>
          </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

    <sect1 label="4.2" id="Font-sizes">
      <title>Font sizes</title>
      <para><indexterm role="cp"><primary>font sizes</primary></indexterm><indexterm role="cp"><primary>typeface sizes</primary></indexterm><indexterm role="cp"><primary>sizes of text</primary></indexterm>
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 &lsquo;<literal>10pt</literal>&rsquo;, &lsquo;<literal>11pt</literal>&rsquo;, and
&lsquo;<literal>12pt</literal>&rsquo; document size options, respectively (see <xref linkend="Document-class-options"></xref>).</para>
      <para><indexterm role="fn"><primary>\tiny</primary></indexterm><indexterm role="fn"><primary>\scriptsize</primary></indexterm><indexterm role="fn"><primary>\footnotesize</primary></indexterm><indexterm role="fn"><primary>\small</primary></indexterm><indexterm role="fn"><primary>\normalsize</primary></indexterm><indexterm role="fn"><primary>\large</primary></indexterm><indexterm role="fn"><primary>\Large</primary></indexterm><indexterm role="fn"><primary>\LARGE</primary></indexterm><indexterm role="fn"><primary>\huge</primary></indexterm><indexterm role="fn"><primary>\Huge</primary></indexterm></para>
      <informaltable>
        <tgroup cols="4">
          <colspec colwidth="42*"></colspec>
          <colspec colwidth="7*"></colspec>
          <colspec colwidth="7*"></colspec>
          <colspec colwidth="7*"></colspec>
          <thead>
            <row>
              <entry>Command</entry>
              <entry><literal>10pt</literal></entry>
              <entry><literal>11pt</literal></entry>
              <entry><literal>12pt</literal></entry>
            </row>
          </thead>
          <tbody>
            <row>
              <entry><literal>\tiny</literal></entry>
              <entry>5</entry>
              <entry>6</entry>
              <entry>6</entry>
            </row>
            <row>
              <entry><literal>\scriptsize</literal></entry>
              <entry>7</entry>
              <entry>8</entry>
              <entry>8</entry>
            </row>
            <row>
              <entry><literal>\footnotesize</literal></entry>
              <entry>8</entry>
              <entry>9</entry>
              <entry>10</entry>
            </row>
            <row>
              <entry><literal>\small</literal></entry>
              <entry>9</entry>
              <entry>10</entry>
              <entry>10.95</entry>
            </row>
            <row>
              <entry><literal>\normalsize</literal> (default)</entry>
              <entry>10</entry>
              <entry>10.95</entry>
              <entry>12</entry>
            </row>
            <row>
              <entry><literal>\large</literal></entry>
              <entry>12</entry>
              <entry>12</entry>
              <entry>14.4</entry>
            </row>
            <row>
              <entry><literal>\Large</literal></entry>
              <entry>14.4</entry>
              <entry>14.4</entry>
              <entry>17.28</entry>
            </row>
            <row>
              <entry><literal>\LARGE</literal></entry>
              <entry>17.28</entry>
              <entry>17.28</entry>
              <entry>20.74</entry>
            </row>
            <row>
              <entry><literal>\huge</literal></entry>
              <entry>20.74</entry>
              <entry>20.74</entry>
              <entry>24.88</entry>
            </row>
            <row>
              <entry><literal>\Huge</literal></entry>
              <entry>24.88</entry>
              <entry>24.88</entry>
              <entry>24.88</entry>
            </row>
          </tbody>
        </tgroup>
      </informaltable>
      <para>The commands as listed here are &ldquo;declaration forms&rdquo;. The scope of
the declaration form lasts until the next type style command or the
end of the current group.  You can also use the environment form of
these commands; for instance, <literal>\begin{tiny}...\end{tiny}</literal>.</para>
    </sect1>

    <sect1 label="4.3" id="Low-level-font-commands">
      <title>Low-level font commands</title>
      <para><indexterm role="cp"><primary>low-level font commands</primary></indexterm><indexterm role="cp"><primary>font commands, low-level</primary></indexterm>
These commands are primarily intended for writers of macros and
packages.  The commands listed here are only a subset of the available
ones.</para>
      <variablelist>
        <varlistentry>
          <term><literal>\fontencoding{enc}</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\fontencoding</primary></indexterm>Select font encoding. Valid encodings include <literal>OT1</literal> and <literal>T1</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\fontfamily{family}</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\fontfamily</primary></indexterm>Select font family. Valid families include:</para>
            <itemizedlist mark="bullet">
              <listitem>
                <para><literal>cmr</literal>  for Computer Modern Roman</para>
              </listitem>
              <listitem>
                <para><literal>cmss</literal> for Computer Modern Sans Serif</para>
              </listitem>
              <listitem>
                <para><literal>cmtt</literal> for Computer Modern Typewriter</para>
              </listitem>
            </itemizedlist>
            <para>and numerous others.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\fontseries{series}</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\fontseries</primary></indexterm>Select font series. Valid series include:</para>
            <itemizedlist mark="bullet">
              <listitem>
                <para><literal>m</literal>  Medium (normal)</para>
              </listitem>
              <listitem>
                <para><literal>b</literal>  Bold</para>
              </listitem>
              <listitem>
                <para><literal>c</literal>  Condensed</para>
              </listitem>
              <listitem>
                <para><literal>bc</literal> Bold condensed</para>
              </listitem>
              <listitem>
                <para><literal>bx</literal> Bold extended</para>
              </listitem>
            </itemizedlist>
            <para>and various other combinations.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\fontshape{shape}</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\fontshape</primary></indexterm>Select font shape. Valid shapes are:</para>
            <itemizedlist mark="bullet">
              <listitem>
                <para><literal>n</literal>  Upright (normal)</para>
              </listitem>
              <listitem>
                <para><literal>it</literal> Italic</para>
              </listitem>
              <listitem>
                <para><literal>sl</literal> Slanted (oblique)</para>
              </listitem>
              <listitem>
                <para><literal>sc</literal> Small caps</para>
              </listitem>
              <listitem>
                <para><literal>ui</literal> Upright italics</para>
              </listitem>
              <listitem>
                <para><literal>ol</literal> Outline</para>
              </listitem>
            </itemizedlist>
            <para>The two last shapes are not available for most font families.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\fontsize{size}{skip}</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\fontsize</primary></indexterm><indexterm role="fn"><primary>\baselineskip</primary></indexterm>Set font size. The first parameter is the font size to switch to and
the second is the line spacing to use; this is stored in a parameter
named <literal>\baselineskip</literal>.  The unit of both parameters defaults to
pt.  The default <literal>\baselineskip</literal> for the Computer Modern typeface
is 1.2 times the <literal>\fontsize</literal>.</para>
            <para><indexterm role="fn"><primary>\baselinestretch</primary></indexterm><indexterm role="cp"><primary><literal>setspace</literal> package</primary></indexterm>The line spacing is also multiplied by the value of the
<literal>\baselinestretch</literal> parameter when the type size changes; the
default is 1.  However, the best way to &ldquo;double space&rdquo; a document,
if you should be unlucky enough to have to produce such, is to use the
<literal>setspace</literal> package; see
<ulink url="http://www.tex.ac.uk/cgi-bin/texfaq2html?label=linespace">http://www.tex.ac.uk/cgi-bin/texfaq2html?label=linespace</ulink>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\selectfont</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\selectfont</primary></indexterm>The changes made by calling the four font commands described above do
not come into effect until <literal>\selectfont</literal> is called.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\usefont{enc}{family}{series}{shape}</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\usefont</primary></indexterm>The same as invoking <literal>\fontencoding</literal>, <literal>\fontfamily</literal>,
<literal>\fontseries</literal> and <literal>\fontshape</literal> with the given parameters,
followed by <literal>\selectfont</literal>.</para>
          </listitem>
        </varlistentry>
      </variablelist>
    </sect1>
  </chapter>

  <chapter label="5" id="Layout">
    <title>Layout</title>
    <para><indexterm role="cp"><primary>layout commands</primary></indexterm>
Miscellaneous commands for controlling the general layout of the page.</para>

    <sect1 label="5.1" id="\onecolumn">
      <title><literal>\onecolumn</literal></title>
      <para><indexterm role="fn"><primary>\onecolumn</primary></indexterm><indexterm role="cp"><primary>one-column output</primary></indexterm>
The <literal>\onecolumn</literal> declaration starts a new page and produces
single-column output.  This is the default.</para>
    </sect1>

    <sect1 label="5.2" id="\twocolumn">
      <title><literal>\twocolumn</literal></title>
      <para><indexterm role="fn"><primary>\twocolumn</primary></indexterm><indexterm role="cp"><primary>multicolumn text</primary></indexterm><indexterm role="cp"><primary>two-column output</primary></indexterm>
Synopsis:</para>
      <screen>
\twocolumn[<replaceable>text1col</replaceable>]
</screen>
      <para>The <literal>\twocolumn</literal> declaration starts a new page and produces
two-column output. If the optional <replaceable>text1col</replaceable> argument is present,
it is typeset in one-column mode before the two-column typesetting
starts.</para>
      <para>These parameters control typesetting in two-column output:</para>
      <variablelist>
        <varlistentry>
          <term><literal>\columnsep</literal></term>
          <listitem>
            <para>The distance between columns (35pt by default).</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\columnseprule</literal></term>
          <listitem>
            <para>The width of the rule between columns; the default is 0pt, so there is no rule.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\columnwidth</literal></term>
          <listitem>
            <para>The width of the current column; this is equal to <literal>\textwidth</literal> in
single-column text.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>These parameters control float behavior in two-column output:</para>
      <variablelist>
        <varlistentry>
          <term><literal>\dbltopfraction</literal></term>
          <listitem>
            <para>Maximum fraction at the top of a two-column page that may be occupied
by floats.  Default &lsquo;<literal>.7</literal>&rsquo;, can be usefully redefined to (say)
&lsquo;<literal>.9</literal>&rsquo; to avoid going to float pages so soon.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\dblfloatpagefraction</literal></term>
          <listitem>
            <para>The minimum fraction of a float page that must be occupied by floats,
for a two-column float page.  Default &lsquo;<literal>.5</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\dblfloatsep</literal></term>
          <listitem>
            <para>Distance between floats at the top or bottom of a two-column float
page.  Default &lsquo;<literal>12pt plus2pt minus2pt</literal>&rsquo; for &lsquo;<literal>10pt</literal>&rsquo; and
&lsquo;<literal>11pt</literal>&rsquo; documents, &lsquo;<literal>14pt plus2pt minus4pt</literal>&rsquo; for &lsquo;<literal>12pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\dbltextfloatsep</literal></term>
          <listitem>
            <para>Distance between a multi-column float at the top or bottom of a page
and the main text.  Default &lsquo;<literal>20pt plus2pt minus4pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

    <sect1 label="5.3" id="\flushbottom">
      <title><literal>\flushbottom</literal></title>
      <para><indexterm role="fn"><primary>\flushbottom</primary></indexterm>
The <literal>\flushbottom</literal> declaration makes all text pages the same
height, adding extra vertical space where necessary to fill out the
page.</para>
      <para>This is the default if <literal>twocolumn</literal> mode is selected
(see <xref linkend="Document-class-options"></xref>).</para>
    </sect1>

    <sect1 label="5.4" id="\raggedbottom">
      <title><literal>\raggedbottom</literal></title>
      <para><indexterm role="fn"><primary>\raggedbottom</primary></indexterm><indexterm role="cp"><primary>stretch, omitting vertical</primary></indexterm>
The <literal>\raggedbottom</literal> declaration makes all pages the natural
height of the material on that page.  No rubber lengths will be
stretched.</para>
    </sect1>

    <sect1 label="5.5" id="Page-layout-parameters">
      <title>Page layout parameters</title>
      <para><indexterm role="cp"><primary>page layout parameters</primary></indexterm><indexterm role="cp"><primary>parameters, page layout</primary></indexterm><indexterm role="cp"><primary>layout, page parameters for</primary></indexterm><indexterm role="cp"><primary>header, parameters for</primary></indexterm><indexterm role="cp"><primary>footer, parameters for</primary></indexterm><indexterm role="cp"><primary>running header and footer</primary></indexterm></para>
      <variablelist>
        <varlistentry>
          <term><literal>\headheight</literal></term>
          <listitem>
            <para>Height of the box that contains the running head.  Default is
&lsquo;<literal>30pt</literal>&rsquo;, except in the <literal>book</literal> class, where it varies with the
type size.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\headsep</literal></term>
          <listitem>
            <para>Vertical distance between the bottom of the header line and the top of
the main text.  Default is &lsquo;<literal>25pt</literal>&rsquo;, except in the <literal>book</literal>
class, where it varies with the type size.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\footskip</literal></term>
          <listitem>
            <para>Distance from the baseline of the last line of text to the baseline of
the page footer.  Default is &lsquo;<literal>30pt</literal>&rsquo;, except in the <literal>book</literal>
class, where it varies with the type size.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\linewidth</literal></term>
          <listitem>
            <para>Width of the current line; the default varies with the font size,
paper width, two-column mode, etc.  For an <literal>article</literal> document in
&lsquo;<literal>10pt</literal>&rsquo;, it's set to &lsquo;<literal>345pt</literal>&rsquo;; in two-column mode, that
becomes &lsquo;<literal>229.5pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textheight</literal></term>
          <listitem>
            <para>The normal vertical height of the page body; the default varies with
the font size, document class, etc.  For an <literal>article</literal> or
<literal>report</literal> document in &lsquo;<literal>10pt</literal>&rsquo;, it's set to
&lsquo;<literal>43\baselineskip</literal>&rsquo;; for <literal>book</literal>, it's &lsquo;<literal>41\baselineskip</literal>&rsquo;.
For &lsquo;<literal>11pt</literal>&rsquo;, it's &lsquo;<literal>38\baselineskip</literal>&rsquo; and for &lsquo;<literal>12pt</literal>&rsquo;,
&lsquo;<literal>36\baselineskip</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textwidth</literal></term>
          <listitem>
            <para>The normal horizontal width of the page body; the default varies as
usual.  For an <literal>article</literal> or <literal>report</literal> document, it's
&lsquo;<literal>345pt</literal>&rsquo; at &lsquo;<literal>10pt</literal>&rsquo;, &lsquo;<literal>360pt</literal>&rsquo; at &lsquo;<literal>11pt</literal>&rsquo;, and
&lsquo;<literal>390pt</literal>&rsquo; at &lsquo;<literal>12pt</literal>&rsquo;.  For a <literal>book</literal> document, it's
&lsquo;<literal>4.5in</literal>&rsquo; at &lsquo;<literal>10pt</literal>&rsquo;, and &lsquo;<literal>5in</literal>&rsquo; at &lsquo;<literal>11pt</literal>&rsquo; or &lsquo;<literal>12pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\topmargin</literal></term>
          <listitem>
            <para>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 default is computed
based on many other parameters: <literal>\paperheight &minus; 2in &minus;
\headheight &minus; \headsep &minus; \textheight &minus; \footskip</literal>, and
then divided by two.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\topskip</literal></term>
          <listitem>
            <para>Minimum distance between the top of the page body and the baseline of
the first line of text.  For the standard clases, the default is the
same as the font size, e.g., &lsquo;<literal>10pt</literal>&rsquo; at &lsquo;<literal>10pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
      </variablelist>
    </sect1>
  </chapter>

  <chapter label="6" id="Sectioning">
    <title>Sectioning</title>
    <para><indexterm role="cp"><primary>sectioning</primary></indexterm>
Sectioning commands provide the means to structure your text into units:</para>
    <variablelist>
      <varlistentry>
        <term><literal>\part</literal></term>
        <term><literal>\chapter</literal></term>
        <listitem>
          <para>(report and book class only)</para>
        </listitem>
      </varlistentry>
      <varlistentry>
        <term><literal>\section</literal></term>
        <term><literal>\subsection</literal></term>
        <term><literal>\subsubsection</literal></term>
        <term><literal>\paragraph</literal></term>
        <term><literal>\subparagraph</literal></term>
      </varlistentry>
    </variablelist>
    <para>All sectioning commands take the same general form, e.g.,</para>
    <screen>
\chapter[<replaceable>toctitle</replaceable>]{<replaceable>title</replaceable>}
</screen>
    <para>In addition to providing the heading <replaceable>title</replaceable> in the main text, the
section title can appear in two other places:</para>
    <orderedlist numeration="arabic">
      <listitem>
        <para>The table of contents.</para>
      </listitem>
      <listitem>
        <para>The running head at the top of the page.</para>
      </listitem>
    </orderedlist>
    <para>You may not want the same text in these places as in the main text.
To handle this, the sectioning commands have an optional argument
<replaceable>toctitle</replaceable> that, when given, specifies the text for these other
places.</para>
    <para><indexterm role="cp"><primary>*-form of sectioning commands</primary></indexterm>Also, all sectioning commands have <literal>*</literal>-forms that print
<replaceable>title</replaceable> as usual, but do not include a number and do not make an
entry in the table of contents.  For instance:</para>
    <screen>
\section*{Preamble}
</screen>
    <para><indexterm role="fn"><primary>\appendix</primary></indexterm><indexterm role="cp"><primary>appendix, creating</primary></indexterm>The <literal>\appendix</literal> command changes the way following sectional units
are numbered.  The <literal>\appendix</literal> command itself generates no text
and does not affect the numbering of parts.  The normal use of this
command is something like</para>
    <screen>
\chapter{A Chapter}
&hellip;
\appendix
\chapter{The First Appendix}
</screen>
  </chapter>

  <chapter label="7" id="Cross-references">
    <title>Cross references</title>
    <para><indexterm role="cp"><primary>cross references</primary></indexterm>
One reason for numbering things like figures and equations is to refer
the reader to them, as in &ldquo;See Figure 3 for more details.&rdquo;</para>

    <sect1 label="7.1" id="\label">
      <title><literal>\label</literal></title>
      <para><indexterm role="fn"><primary>\label</primary></indexterm>
Synopsis:</para>
      <screen>
\label{<replaceable>key</replaceable>}
</screen>
      <para>A <literal>\label</literal> command appearing in ordinary text assigns to
<replaceable>key</replaceable> the number of the current sectional unit; one appearing
inside a numbered environment assigns that number to <replaceable>key</replaceable>.</para>
      <para>A <replaceable>key</replaceable> name can consist of any sequence of letters, digits, or
punctuation characters.  Upper and lowercase letters are distinguished.</para>
      <para>To avoid accidentally creating two labels with the same name, it is
common to use labels consisting of a prefix and a suffix separated by
a colon or period. Some conventionally-used prefixes:</para>
      <variablelist>
        <varlistentry>
          <term><literal>ch</literal></term>
          <listitem>
            <para>for chapters</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>sec</literal></term>
          <listitem>
            <para>for lower-level sectioning commands</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>fig</literal></term>
          <listitem>
            <para>for figures</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>tab</literal></term>
          <listitem>
            <para>for tables</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>eq</literal></term>
          <listitem>
            <para>for equations</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>Thus, a label for a figure would look like <literal>fig:snark</literal> or
<literal>fig.snark</literal>.</para>
    </sect1>

    <sect1 label="7.2" id="\pageref">
      <title><literal>\pageref{<replaceable>key</replaceable>}</literal></title>
      <para><indexterm role="fn"><primary>\pageref</primary></indexterm><indexterm role="cp"><primary>cross referencing with page number</primary></indexterm><indexterm role="cp"><primary>page number, cross referencing</primary></indexterm>
Synopsis:</para>
      <screen>
\pageref{<replaceable>key</replaceable>}
</screen>
      <para>The <literal>\pageref</literal>{<replaceable>key</replaceable>} command produces the page number of
the place in the text where the corresponding
<literal>\label</literal>{<replaceable>key</replaceable>} command appears.</para>
    </sect1>

    <sect1 label="7.3" id="\ref">
      <title><literal>\ref{<replaceable>key</replaceable>}</literal></title>
      <para><indexterm role="fn"><primary>\ref</primary></indexterm><indexterm role="cp"><primary>cross referencing, symbolic</primary></indexterm><indexterm role="cp"><primary>section number, cross referencing</primary></indexterm><indexterm role="cp"><primary>equation number, cross referencing</primary></indexterm><indexterm role="cp"><primary>figure number, cross referencing</primary></indexterm><indexterm role="cp"><primary>footnote number, cross referencing</primary></indexterm>
Synopsis:</para>
      <screen>
\ref{<replaceable>key</replaceable>}
</screen>
      <para>The <literal>\ref</literal> command produces the number of the sectional unit,
equation, footnote, figure, &hellip;, of the corresponding
<literal>\label</literal> command (see <xref linkend="\label"></xref>).  It does not produce any text,
such as the word `Section' or `Figure', just the bare number itself.</para>
    </sect1>
  </chapter>

  <chapter label="8" id="Environments">
    <title>Environments</title>
    <para><indexterm role="cp"><primary>environments</primary></indexterm>
<indexterm role="fn"><primary>\begin</primary></indexterm><indexterm role="fn"><primary>\end</primary></indexterm>
&latex; provides many environments for marking off certain text.
Each environment begins and ends in the same manner:</para>
    <screen>
\begin{<replaceable>envname</replaceable>}
...
\end{<replaceable>envname</replaceable>}
</screen>
    <sect1 label="8.1" id="abstract">
      <title><literal>abstract</literal></title>
      <para><indexterm role="fn"><primary>abstract environment</primary></indexterm><indexterm role="cp"><primary>abstracts</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{abstract}
...
\end{abstract}
</screen>
      <para>Environment for producing an abstract, possibly of multiple paragraphs.</para>
    </sect1>

    <sect1 label="8.2" id="array">
      <title><literal>array</literal></title>
      <para><indexterm role="fn"><primary>array environment</primary></indexterm><indexterm role="cp"><primary>arrays, math</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{array}{<replaceable>template</replaceable>}
<replaceable>col1 text</replaceable>&amp;<replaceable>col1 text</replaceable>&amp;<replaceable>coln</replaceable>}\\
...
\end{array}
</screen>
      <para>Math arrays are produced with the <literal>array</literal> environment, normally
within an <literal>equation</literal> environment (see <xref linkend="equation"></xref>).  It has a
single mandatory <replaceable>template</replaceable> argument describing the number of
columns and the alignment within them.  Each column <replaceable>col</replaceable> is
specified by a single letter that tells how items in that row should
be formatted, as follows:</para>
      <variablelist>
        <varlistentry>
          <term><literal>c</literal></term>
          <listitem>
            <para>centered</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>l</literal></term>
          <listitem>
            <para>flush left</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>r</literal></term>
          <listitem>
            <para>flush right</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para><indexterm role="fn"><primary>\\ (for <literal>array</literal>)</primary></indexterm>Column entries are separated by <literal>&amp;</literal>.  Column entries may include
other &latex; commands.  Each row of the array is terminated with
<literal>\\</literal>.</para>
      <para><indexterm role="fn"><primary>@{...}</primary></indexterm>In the template, the construct <literal>@{<replaceable>text</replaceable>}</literal> puts <replaceable>text</replaceable>
between columns in each row.</para>
      <para>Here's an example:</para>
      <screen>
\begin{equation}
  \begin{array}{lrc}
  left1 &amp; right1 &amp; centered1 \\
  left2 &amp; right2 &amp; centered2 \\
  \end{array}
\end{equation}
</screen>
      <para><indexterm role="fn"><primary>\arraycolsep</primary></indexterm>The <literal>\arraycolsep</literal> parameter defines half the width of the space
separating columns; the default is &lsquo;<literal>5pt</literal>&rsquo;.  See <xref linkend="tabular"></xref>, for other
parameters which affect formatting in <literal>array</literal> environments,
namely <literal>\arrayrulewidth</literal> and <literal>\arraystretch</literal>.</para>
      <para>The <literal>array</literal> environment can only be used in math mode.</para>
    </sect1>

    <sect1 label="8.3" id="center">
      <title><literal>center</literal></title>
      <para><indexterm role="fn"><primary>center environment</primary></indexterm><indexterm role="cp"><primary>centering text, environment for</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{center}
<replaceable>line1</replaceable> \\
<replaceable>line2</replaceable> \\
\end{center}
</screen>
      <para><indexterm role="fn"><primary>\\ (for <literal>center</literal>)</primary></indexterm>The <literal>center</literal> environment allows you to create a paragraph
consisting of lines that are centered within the left and right
margins on the current page.  Each line is terminated with the
string <literal>\\</literal>.</para>

      <sect2 label="8.3.1" id="\centering">
        <title><literal>\centering</literal></title>
        <para><indexterm role="fn"><primary>\centering</primary></indexterm><indexterm role="cp"><primary>centering text, declaration for</primary></indexterm>
The <literal>\centering</literal> declaration corresponds to the <literal>center</literal>
environment.  This declaration can be used inside an environment such
as <literal>quote</literal> or in a <literal>parbox</literal>.  Thus, the text of a figure or
table can be centered on the page by putting a <literal>\centering</literal>
command at the beginning of the figure or table environment.</para>
        <para>Unlike the <literal>center</literal> environment, the <literal>\centering</literal> command
does not start a new paragraph; it simply changes how &latex; formats
paragraph units.  To affect a paragraph unit's format, the scope of
the declaration must contain the blank line or <literal>\end</literal> command (of
an environment such as quote) that ends the paragraph unit.</para>
        <para>Here's an example:</para>
        <screen>
\begin{quote}
\centering
first line \\
second line \\
\end{quote}
</screen>
      </sect2>
    </sect1>

    <sect1 label="8.4" id="description">
      <title><literal>description</literal></title>
      <para><indexterm role="fn"><primary>description environment</primary></indexterm><indexterm role="cp"><primary>labelled lists, creating</primary></indexterm><indexterm role="cp"><primary>description lists, creating</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{description}
\item [<replaceable>label1</replaceable>] <replaceable>item1</replaceable>
\item [<replaceable>label2</replaceable>] <replaceable>item2</replaceable>
...
\end{description}
</screen>
      <para><indexterm role="fn"><primary>\item</primary></indexterm>The <literal>description</literal> environment is used to make labelled lists.  Each
<replaceable>label</replaceable> is typeset in bold, flush right.  The <replaceable>item</replaceable> text may
contain multiple paragraphs.</para>
      <para><indexterm role="cp"><primary>bold typewriter, avoiding</primary></indexterm><indexterm role="cp"><primary>typewriter labels in lists</primary></indexterm>Another variation: since the bold style is applied to the labels, if
you typeset a label in typewriter using <literal>\texttt</literal>, you'll get
bold typewriter: <literal>\item[\texttt{bold and typewriter}]</literal>.  This
may be too bold, among other issues.  To get just typewriter, use
<literal>\tt</literal>, which resets all other style variations: <literal>\item[{\tt
plain typewriter}]</literal>.</para>
      <para>For details about list spacing, see <xref linkend="itemize"></xref>.</para>
    </sect1>

    <sect1 label="8.5" id="displaymath">
      <title><literal>displaymath</literal></title>
      <para><indexterm role="fn"><primary>displaymath environment</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{displaymath}
<replaceable>math</replaceable>
\end{displaymath}
</screen>
      <para role="continues">or</para>
      <screen>
\[<replaceable>math</replaceable>\]
</screen>
      <para>The <literal>displaymath</literal> environment (<literal>\[...\]</literal> is a synonym)
typesets the <replaceable>math</replaceable> text on its own line, centered by default.
The global <literal>fleqn</literal> option makes equations flush left; see
<xref linkend="Document-class-options"></xref>.</para>
      <para>No equation number is added to <literal>displaymath</literal> text; to get an
equation number, use the <literal>equation</literal> environment (see <xref linkend="equation"></xref>).</para>
    </sect1>

    <sect1 label="8.6" id="document">
      <title><literal>document</literal></title>
      <para><indexterm role="fn"><primary>document environment</primary></indexterm>
The <literal>document</literal> environment encloses the body of a document.
It is required in every &latex; document.  See <xref linkend="Starting-&-ending"></xref>.</para>
    </sect1>

    <sect1 label="8.7" id="enumerate">
      <title><literal>enumerate</literal></title>
      <para><indexterm role="fn"><primary>enumerate environment</primary></indexterm><indexterm role="cp"><primary>lists of items, numbered</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{enumerate}
\item <replaceable>item1</replaceable>
\item <replaceable>item2</replaceable>
...
\end{enumerate}
</screen>
      <para>The <literal>enumerate</literal> environment produces a numbered list.  Enumerations
can be nested within one another, up to four levels deep.  They can also
be nested within other paragraph-making environments, such as
<literal>itemize</literal> (see <xref linkend="itemize"></xref>) and <literal>description</literal>
(see <xref linkend="description"></xref>).</para>
      <para><indexterm role="fn"><primary>\item</primary></indexterm>Each item of an enumerated list begins with an <literal>\item</literal> command.
There must be at least one <literal>\item</literal> command within the environment.</para>
      <para>By default, the numbering at each level is done like this:</para>
      <orderedlist numeration="arabic">
        <listitem>
          <para>1., 2., &hellip;</para>
        </listitem>
        <listitem>
          <para>(a), (b), &hellip;</para>
        </listitem>
        <listitem>
          <para>i., ii., &hellip;</para>
        </listitem>
        <listitem>
          <para>A., B., &hellip;</para>
        </listitem>
      </orderedlist>
      <para><indexterm role="fn"><primary>\enumi</primary></indexterm><indexterm role="fn"><primary>\enumii</primary></indexterm><indexterm role="fn"><primary>\enumiii</primary></indexterm><indexterm role="fn"><primary>\enumiv</primary></indexterm>The <literal>enumerate</literal> environment uses the counters <literal>\enumi</literal>
through <literal>\enumiv</literal> counters (see <xref linkend="Counters"></xref>).  If the optional
argument to <literal>\item</literal> is given, the counter is not incremented for
that item.</para>
      <para><indexterm role="fn"><primary>\labelenumi</primary></indexterm><indexterm role="fn"><primary>\labelenumii</primary></indexterm><indexterm role="fn"><primary>\labelenumiii</primary></indexterm><indexterm role="fn"><primary>\labelenumiv</primary></indexterm>The <literal>enumerate</literal> environment uses the commands <literal>\labelenumi</literal>
through <literal>\labelenumiv</literal> to produce the default label.  So, you can
use <literal>\renewcommand</literal> to change the labels (see <xref linkend="\newcommand-&-\renewcommand"></xref>).  For instance, to have the first level use uppercase
letters:</para>
      <para><indexterm role="fn"><primary>\Alph example</primary></indexterm></para>
      <screen>
\renewcommand{\labelenumi}{\Alph{enumi}}
</screen>
    </sect1>

    <sect1 label="8.8" id="eqnarray">
      <title><literal>eqnarray</literal></title>
      <para><indexterm role="fn"><primary>eqnarray environment</primary></indexterm><indexterm role="cp"><primary>equations, aligning</primary></indexterm><indexterm role="cp"><primary>aligning Equations</primary></indexterm></para>
      <screen>
\begin{eqnarray}  <lineannotation>(or <literal>eqnarray*</literal>)</lineannotation>
<replaceable>formula1</replaceable> \\
<replaceable>formula2</replaceable> \\
...
\end{eqnarray}
</screen>
      <para><indexterm role="fn"><primary>\\ (for <literal>eqnarray</literal>)</primary></indexterm>The <literal>eqnarray</literal> environment is used to display a sequence of
equations or inequalities.  It is very much like a three-column
<literal>array</literal> environment, with consecutive rows separated by <literal>\\</literal>
and consecutive items within a row separated by an <literal>&amp;</literal>.</para>
      <para><indexterm role="fn"><primary>\\* (for <literal>eqnarray</literal>)</primary></indexterm><literal>\\*</literal> can also be used to separate equations, with its normal
meaning of not allowing a page break at that line.</para>
      <para><indexterm role="fn"><primary>\nonumber</primary></indexterm><indexterm role="cp"><primary>equation numbers, omitting</primary></indexterm>An equation number is placed on every line unless that line has a
<literal>\nonumber</literal> command.  Alternatively, The <literal>*</literal>-form of the
environment (<literal>\begin{eqnarray*} ... \end{eqnarray*}</literal>) will
omit equation numbering entirely, while otherwise being the same as
<literal>eqnarray</literal>.</para>
      <para><indexterm role="fn"><primary>\lefteqn</primary></indexterm>The command <literal>\lefteqn</literal> is used for splitting long formulas across
lines. It typesets its argument in display style flush left in a box of
zero width.</para>
    </sect1>

    <sect1 label="8.9" id="equation">
      <title><literal>equation</literal></title>
      <para><indexterm role="fn"><primary>equation environment</primary></indexterm><indexterm role="cp"><primary>equations, environment for</primary></indexterm><indexterm role="cp"><primary>formulas, environment for</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{equation}
<replaceable>math</replaceable>
\end{equation}
</screen>
      <para>The <literal>equation</literal> environment starts a <literal>displaymath</literal>
environment (see <xref linkend="displaymath"></xref>), e.g., centering the <replaceable>math</replaceable> text
on the page, and also places an equation number in the right margin.</para>
    </sect1>

    <sect1 label="8.10" id="figure">
      <title><literal>figure</literal></title>
      <para><indexterm role="fn"><primary>figure</primary></indexterm><indexterm role="cp"><primary>inserting figures</primary></indexterm><indexterm role="cp"><primary>figures, inserting</primary></indexterm></para>
      <screen>
\begin{figure}[<replaceable>placement</replaceable>]
<replaceable>figbody</replaceable>
\label{<replaceable>label}</replaceable>
\caption[<replaceable>loftitle</replaceable>]{<replaceable>text</replaceable>}
\end{figure}
</screen>
      <para>Figures are objects that are not part of the normal text, and are
instead &ldquo;floated&rdquo; to a convenient place, such as the top of a page.
Figures will not be split between two pages.</para>
      <para>The optional argument <literal>[placement]</literal> determines where &latex; will try
to place your figure.  There are four places where &latex; can possibly
put a float:</para>
      <orderedlist numeration="arabic">
        <listitem>
          <para><literal>h</literal> (Here) - at the position in the text where the figure
environment appears.</para>
        </listitem>
        <listitem>
          <para><literal>t</literal> (Top) - at the top of a text page.</para>
        </listitem>
        <listitem>
          <para><literal>b</literal> (Bottom) - at the bottom of a text page.</para>
        </listitem>
        <listitem>
          <para><literal>p</literal> (Page of floats) - on a separate float page, which is a page
containing no text, only floats.</para>
        </listitem>
      </orderedlist>
      <para>The standard report and article classes use the default placement
<literal>tbp</literal>.</para>
      <para>The body of the figure is made up of whatever text, &latex; commands, etc.
you wish.</para>
      <para><indexterm role="fn"><primary>\caption</primary></indexterm>The <literal>\caption</literal> command specifies caption <replaceable>text</replaceable> for the
figure.  The caption is numbered by default.  If <replaceable>loftitle</replaceable> is
present, it is used in the list of figures instead of <replaceable>text</replaceable>
(see <xref linkend="Tables-of-contents"></xref>).</para>
<!-- xx float-placement, float-caption sections? -->
      <variablelist>
        <title><indexterm role="fn"><primary>\bottomfraction</primary></indexterm>The maximum fraction of the page allowed to be occuped by floats atthe bottom; default &lsquo;<literal>.3</literal>&rsquo;.</title>
        <varlistentry>
          <term><literal>\floatpagefraction</literal></term>
          <listitem>
            <para>The minimum fraction of a float page that must be occupied by floats;
default &lsquo;<literal>.5</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\floatsep</literal></term>
          <listitem>
            <para>Space between floats at the top or bottom of a page; default
&lsquo;<literal>12pt plus2pt minus2pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\intextsep</literal></term>
          <listitem>
            <para>Space above and below a float in the middle of the main text; default
&lsquo;<literal>12pt plus2pt minus2pt</literal>&rsquo; for &lsquo;<literal>10pt</literal>&rsquo; and &lsquo;<literal>11pt</literal>&rsquo; styles,
&lsquo;<literal>14pt plus4pt minus4pt</literal>&rsquo; for &lsquo;<literal>12pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textfloatsep</literal></term>
          <listitem>
            <para>Space between the last (first) float at the top (bottom) of a page;
default &lsquo;<literal>20pt plus2pt minus4pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\textfraction</literal></term>
          <listitem>
            <para>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 &lsquo;<literal>.2</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\topfraction</literal></term>
          <listitem>
            <para>Maximum fraction at the top of a page that may be occupied before
floats; default is &lsquo;<literal>.7</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
      </variablelist>
    </sect1>

    <sect1 label="8.11" id="flushleft">
      <title><literal>flushleft</literal></title>
      <para><indexterm role="fn"><primary>flushleft environment</primary></indexterm><indexterm role="cp"><primary>left-justifying text, environment for</primary></indexterm><indexterm role="cp"><primary>ragged right text, environment for</primary></indexterm></para>
      <screen>
\begin{flushleft}
<replaceable>line1</replaceable> \\
<replaceable>line2</replaceable> \\
...
\end{flushleft}
</screen>
      <para><indexterm role="fn"><primary>\\ for <literal>flushleft</literal></primary></indexterm>The <literal>flushleft</literal> environment allows you to create a paragraph
consisting of lines that are flush to the left-hand margin and ragged
right Each line must be terminated with the string <literal>\\</literal>.</para>

      <sect2 label="8.11.1" id="\raggedright">
        <title><literal>\raggedright</literal></title>
        <para><indexterm role="fn"><primary>\raggedright</primary></indexterm><indexterm role="cp"><primary>ragged right text</primary></indexterm><indexterm role="cp"><primary>left-justifying text</primary></indexterm><indexterm role="cp"><primary>justification, ragged right</primary></indexterm>
The <literal>\raggedright</literal> declaration corresponds to the
<literal>flushleft</literal> environment.  This declaration can be used inside an
environment such as <literal>quote</literal> or in a <literal>parbox</literal>.</para>
        <para>Unlike the <literal>flushleft</literal> environment, the <literal>\raggedright</literal>
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 <literal>\end</literal>
command that ends the paragraph unit.</para>
      </sect2>
    </sect1>

    <sect1 label="8.12" id="flushright">
      <title><literal>flushright</literal></title>
      <para><indexterm role="fn"><primary>flushright environment</primary></indexterm><indexterm role="cp"><primary>ragged left text, environment for</primary></indexterm><indexterm role="cp"><primary>right-justifying text, environment for</primary></indexterm></para>
      <screen>
\begin{flushright}
<replaceable>line1</replaceable> \\
<replaceable>line2</replaceable> \\
...
\end{flushright}
</screen>
      <para><indexterm role="fn"><primary>\\ (for <literal>flushright</literal>)</primary></indexterm>The <literal>flushright</literal> environment allows you to create a paragraph
consisting of lines that are flush to the right-hand margin and ragged
left.  Each line must be terminated with the string <literal>\\</literal>.</para>

      <sect2 label="8.12.1" id="\raggedleft">
        <title><literal>\raggedleft</literal></title>
        <para><indexterm role="fn"><primary>\raggedleft</primary></indexterm><indexterm role="cp"><primary>ragged left text</primary></indexterm><indexterm role="cp"><primary>justification, ragged left</primary></indexterm><indexterm role="cp"><primary>right-justifying text</primary></indexterm>
The <literal>\raggedleft</literal> declaration corresponds to the
<literal>flushright</literal> environment.  This declaration can be used inside an
environment such as <literal>quote</literal> or in a <literal>parbox</literal>.</para>
        <para>Unlike the <literal>flushright</literal> environment, the <literal>\raggedleft</literal>
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 <literal>\end</literal>
command that ends the paragraph unit.</para>
      </sect2>
    </sect1>

    <sect1 label="8.13" id="itemize">
      <title><literal>itemize</literal></title>
      <para><indexterm role="fn"><primary>itemize environment</primary></indexterm><indexterm role="fn"><primary>\item</primary></indexterm><indexterm role="cp"><primary>lists of items</primary></indexterm><indexterm role="cp"><primary>unordered lists</primary></indexterm><indexterm role="cp"><primary>bulleted lists</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{itemize}
\item <replaceable>item1</replaceable>
\item <replaceable>item2</replaceable>
...
\end{itemize}
</screen>
      <para>The <literal>itemize</literal> environment produces an &ldquo;unordered&rdquo;, &ldquo;bulleted&rdquo;
list.  Itemizations can be nested within one another, up to four
levels deep.  They can also be nested within other paragraph-making
environments, such as <literal>enumerate</literal> (see <xref linkend="enumerate"></xref>).</para>
      <para>Each item of an <literal>itemize</literal> list begins with an <literal>\item</literal> command.
There must be at least one <literal>\item</literal> command within the environment.</para>
      <para>By default, the marks at each level look like this:</para>
      <orderedlist numeration="arabic">
        <listitem>
          <para>&bull;</para>
        </listitem>
        <listitem>
          <para><emphasis role="bold">--<!-- /@w --></emphasis> (bold en-dash)</para>
        </listitem>
        <listitem>
          <para>*</para>
        </listitem>
        <listitem>
          <para>. (centered dot, rendered here as a period)</para>
        </listitem>
      </orderedlist>
      <para><indexterm role="fn"><primary>\labelitemi</primary></indexterm><indexterm role="fn"><primary>\labelitemii</primary></indexterm><indexterm role="fn"><primary>\labelitemiii</primary></indexterm><indexterm role="fn"><primary>\labelitemiv</primary></indexterm>The <literal>itemize</literal> environment uses the commands <literal>\labelitemi</literal>
through <literal>\labelitemiv</literal> to produce the default label.  So, you can
use <literal>\renewcommand</literal> to change the labels.  For instance, to have
the first level use diamonds:</para>
      <screen>
\renewcommand{\labelitemi}{$\diamond$}
</screen>
      <para><indexterm role="fn"><primary>\leftmargin</primary></indexterm><indexterm role="fn"><primary>\leftmargini</primary></indexterm><indexterm role="fn"><primary>\leftmarginii</primary></indexterm><indexterm role="fn"><primary>\leftmarginiii</primary></indexterm><indexterm role="fn"><primary>\leftmarginiv</primary></indexterm><indexterm role="fn"><primary>\leftmarginv</primary></indexterm><indexterm role="fn"><primary>\leftmarginvi</primary></indexterm>The <literal>\leftmargini</literal> through <literal>\leftmarginvi</literal> parameters define
the distance between the left margin of the enclosing environment and
the left margin of the list.  By convention, <literal>\leftmargin</literal> is set
to the appropriate <literal>\leftmargin<replaceable>N</replaceable></literal> when a new level of
nesting is entered.</para>
      <para>The defaults vary from &lsquo;<literal>.5em</literal>&rsquo; (highest levels of nesting) to
&lsquo;<literal>2.5em</literal>&rsquo; (first level), and are a bit reduced in two-column mode.
This example greatly reduces the margin space for outermost lists:</para>
      <screen>
\setlength{\leftmargini}{1.25em} % default 2.5em
</screen>
<!-- xx should be in its own generic section -->
      <para>Some parameters that affect list formatting:</para>
      <variablelist>
        <varlistentry>
          <term><literal>\itemindent</literal></term>
          <listitem>
            <para>Extra indentation before each item in a list; default zero.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\labelsep</literal></term>
          <listitem>
            <para>Space between the label and text of an item; default &lsquo;<literal>.5em</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\labelwidth</literal></term>
          <listitem>
            <para>Width of the label; default &lsquo;<literal>2em</literal>&rsquo;, or &lsquo;<literal>1.5em</literal>&rsquo; in two-column mode.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\listparindent</literal></term>
          <listitem>
            <para>Extra indentation added to second and subsequent paragraphs within a
list item; default &lsquo;<literal>0pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\rightmargin</literal></term>
          <listitem>
            <para>Horizontal distance between the right margin of the list and the
enclosing environment; default &lsquo;<literal>0pt</literal>&rsquo;, except in the <literal>quote</literal>,
<literal>quotation</literal>, and <literal>verse</literal> environments, where it is set equal
to <literal>\leftmargin</literal>.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>Parameters affecting vertical spacing between list items (rather
loose, by default).</para>
      <variablelist>
        <varlistentry>
          <term><literal>\itemsep</literal></term>
          <listitem>
            <para>Vertical space between items.  The default is <literal>2pt plus1pt
minus1pt</literal> for <literal>10pt</literal> documents, <literal>3pt plus2pt minus1pt</literal> for
<literal>11pt</literal>, and <literal>4.5pt plus2pt minus1pt</literal> for <literal>12pt</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\parsep</literal></term>
          <listitem>
            <para>Extra vertical space between paragraphs within a list item.  Defaults
are the same as <literal>\itemsep</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\topsep</literal></term>
          <listitem>
            <para>Vertical space between the first item and the preceding paragraph.
The default is <literal>4pt plus2pt minus2pt</literal> for <literal>10pt</literal> documents,
<literal>6pt plus2pt minus2pt</literal> for <literal>11pt</literal>, and <literal>9pt plus3pt
minus5pt</literal> for <literal>12pt</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\partopsep</literal></term>
          <listitem>
            <para>Extra space added to <literal>\topsep</literal> when the list environment starts a
paragraph.  The default is <literal>2pt plus1pt minus1pt</literal> for <literal>10pt</literal>
documents, <literal>3pt plus1pt minus1pt</literal> for <literal>11pt</literal>, and <literal>3pt
plus2pt minus2pt</literal> for <literal>12pt</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\topsep</literal></term>
          <listitem>
            <para>Extra vertical space added before an initial and after a final list
item.  Its value is changed with list level and font size changes; for
instance, within a first-level list at &lsquo;<literal>10pt</literal>&rsquo;, it is &lsquo;<literal>4pt
plus2pt minus2pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para><indexterm role="fn"><primary>\parskip example</primary></indexterm>Especially for lists with short items, it may be desirable to elide
space between items.  Here is an example defining an <literal>itemize*</literal>
environment with no extra spacing between items, or between paragraphs
within a single item (<literal>\parskip</literal> is not list-specific,
see <xref linkend="\parskip"></xref>):</para>
      <screen>
\newenvironment{itemize*}%
  {\begin{itemize}%
    \setlength{\itemsep}{0pt}%
    \setlength{\parsep}{0pt}}%
    \setlength{\parskip}{0pt}}%
  {\end{itemize}}
</screen>
    </sect1>

    <sect1 label="8.14" id="letter">
      <title><literal>letter</literal> environment: writing letters</title>
      <para><indexterm role="fn"><primary>letter</primary></indexterm>
This environment is used for creating letters.  See <xref linkend="Letters"></xref>.</para>
    </sect1>

    <sect1 label="8.15" id="list">
      <title><literal>list</literal></title>
      <para><indexterm role="fn"><primary>list</primary></indexterm><indexterm role="cp"><primary>lists of items, generic</primary></indexterm>
The <literal>list</literal> environment is a generic environment which is used for
defining many of the more specific environments. It is seldom used in
documents, but often in macros.</para>
      <screen>
\begin{list}{<replaceable>labeling</replaceable>}{<replaceable>spacing</replaceable>}
\item <replaceable>item1</replaceable>
\item <replaceable>item2</replaceable>
...
\end{list}
</screen>
      <para>The mandatory <replaceable>labeling</replaceable> argument specifies how items should be
labelled (unless the optional argument is supplied to <literal>\item</literal>).
This argument is a piece of text that is inserted in a box to form the
label.  It can and usually does contain other &latex; commands.</para>
      <para>The mandatory <replaceable>spacing</replaceable> argument contains commands to change the
spacing parameters for the list.  This argument will most often be
empty, i.e., <literal>{}</literal>, which leaves the default spacing.</para>
    </sect1>

    <sect1 label="8.16" id="math">
      <title><literal>math</literal></title>
      <para><indexterm role="fn"><primary>math environment</primary></indexterm><indexterm role="cp"><primary>in-line formulas</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{math}
<replaceable>math</replaceable>
\end{math}
</screen>
      <para>The <literal>math</literal> environment inserts the given <replaceable>math</replaceable> within the
running text.  <literal>\(...\))</literal> and <literal>$...$</literal> are synonyms.
See <xref linkend="Math-formulas"></xref>.</para>
    </sect1>

    <sect1 label="8.17" id="minipage">
      <title><literal>minipage</literal></title>
      <para><indexterm role="fn"><primary>minipage environment</primary></indexterm><indexterm role="cp"><primary>minipage, creating a</primary></indexterm></para>
      <screen>
\begin{minipage}[<replaceable>position</replaceable>]{<replaceable>width</replaceable>}
<replaceable>text</replaceable>
\end{minipage}
</screen>
      <para>The <literal>minipage</literal> environment typesets its body <replaceable>text</replaceable> in a
block that will not be broken across pages (similar to the
<literal>\parbox</literal> command, see <xref linkend="\parbox"></xref>).  You may use other
paragraph-making environments inside a minipage (unlike <literal>\parbox</literal>).</para>
<!-- (xxref positions) -->
      <para>It takes an optional <replaceable>position</replaceable> argument for placing <replaceable>text</replaceable>,
and a mandatory <replaceable>width</replaceable> argument for specifying the line width.</para>
      <para><indexterm role="cp"><primary>indentation of paragraphs, in minipage</primary></indexterm><indexterm role="cp"><primary>paragraph indentation, in minipage</primary></indexterm><indexterm role="fn"><primary>\parindent</primary></indexterm>By default, paragraphs are not indented in the <literal>minipage</literal>
environment.  You can restore indentation with a command such as
<literal>\setlength{\parindent}{1pc}</literal> command.</para>
      <para><indexterm role="cp"><primary>footnotes in figures</primary></indexterm><indexterm role="cp"><primary>figures, footnotes in</primary></indexterm>Footnotes in a <literal>minipage</literal> environment are handled in a way that is
particularly useful for putting footnotes in figures or tables.  A
<literal>\footnote</literal> or <literal>\footnotetext</literal> command puts the footnote at
the bottom of the minipage instead of at the bottom of the page, and it
uses the <literal>\mpfootnote</literal> counter instead of the ordinary
<literal>footnote</literal> counter (see <xref linkend="Counters"></xref>).</para>
      <para>However, don't put one minipage inside another if you are using
footnotes; they may wind up at the bottom of the wrong minipage.</para>
    </sect1>

    <sect1 label="8.18" id="picture">
      <title><literal>picture</literal></title>
      <para><indexterm role="fn"><primary>picture</primary></indexterm><indexterm role="cp"><primary>creating pictures</primary></indexterm><indexterm role="cp"><primary>pictures, creating</primary></indexterm></para>
      <screen>
\begin{picture}(width,height)(x offset,y offset)
&hellip; <replaceable>picture commands</replaceable> &hellip;
\end{picture}
</screen>
      <para><indexterm role="fn"><primary>\unitlength</primary></indexterm>The <literal>picture</literal> environment allows you to create just about any
kind of picture you want containing text, lines, arrows and circles.
You tell &latex; where to put things in the picture by specifying
their coordinates.  A coordinate is a number that may have a decimal
point and a minus sign&mdash;a number like <literal>5</literal>, <literal>0.3</literal> or
<literal>-3.1416</literal>.  A coordinate specifies a length in multiples of the
unit length <literal>\unitlength</literal>, so if <literal>\unitlength</literal> has been set
to <literal>1cm</literal>, then the coordinate 2.54 specifies a length of 2.54
centimeters.  You should only change the value of <literal>\unitlength</literal>,
using the <literal>\setlength</literal> command, outside of a <literal>picture</literal>
environment.</para>
      <para>A position is a pair of coordinates, such as <literal>(2.4,-5)</literal>, specifying
the point with x-coordinate <literal>2.4</literal> and y-coordinate <literal>-5</literal>.
Coordinates are specified in the usual way with respect to an origin,
which is normally at the lower-left corner of the picture.  Note that
when a position appears as an argument, it is not enclosed in braces;
the parentheses serve to delimit the argument.</para>
      <para>The <literal>picture</literal> environment has one mandatory argument, which is a
<literal>position</literal>.  It specifies the size of the picture.  The environment
produces a rectangular box with width and height determined by this
argument's x- and y-coordinates.</para>
      <para>The <literal>picture</literal> environment also has an optional <literal>position</literal>
argument, following the <literal>size</literal> argument, that can change the
origin.  (Unlike ordinary optional arguments, this argument is not
contained in square brackets.) The optional argument gives the
coordinates of the point at the lower-left corner of the picture
(thereby determining the origin).  For example, if <literal>\unitlength</literal>
has been set to <literal>1mm</literal>, the command</para>
      <screen>
   \begin{picture}(100,200)(10,20)
</screen>
      <para>produces a picture of width 100 millimeters and height 200
millimeters, whose lower-left corner is the point (10,20) and whose
upper-right corner is therefore the point (110,220).  When you first
draw a picture, you will omit the optional argument, leaving the origin
at the lower-left corner.  If you then want to modify your picture by
shifting everything, you just add the appropriate optional argument.</para>
      <para>The environment's mandatory argument determines the nominal size of the
picture.  This need bear no relation to how large the picture really is;
&latex; will happily allow you to put things outside the picture, or even
off the page.  The picture's nominal size is used by &latex; in determining
how much room to leave for it.</para>
      <para>Everything that appears in a picture is drawn by the <literal>\put</literal>
command. The command</para>
      <screen>
\put (11.3,-.3){...}
</screen>
      <para role="continues">puts the object specified by <literal>...</literal> in the
picture, with its reference point at coordinates (11.3,-.3).
The reference points for various objects will be described below.</para>
      <para><indexterm role="fn"><primary>lR box</primary></indexterm>The <literal>\put</literal> command creates an <firstterm>LR box</firstterm>.  You can put anything
that can go in an <literal>\mbox</literal> (see <xref linkend="\mbox"></xref>) in the text argument of
the <literal>\put</literal> command.  When you do this, the reference point will
be the lower left corner of the box.</para>
      <para>The <literal>picture</literal> commands are described in the following sections.</para>

      <sect2 label="8.18.1" id="\circle">
        <title><literal>\circle</literal></title>
        <para><indexterm role="fn"><primary>\circle</primary></indexterm></para>
        <screen>
\circle[*]{<replaceable>diameter</replaceable>}
</screen>
        <para>The <literal>\circle</literal> command produces a circle with a diameter as close
to the specified one as possible.  The <literal>*</literal>-form of the command
draws a solid circle.</para>
        <para>Circles up to 40 pt can be drawn.</para>
      </sect2>

      <sect2 label="8.18.2" id="\makebox-(picture)">
        <title><literal>\makebox</literal></title>
        <para><indexterm role="fn"><primary>\makebox (picture)</primary></indexterm>
<literal>\makebox(width,height)[position]{...}</literal></para>
        <para>The <literal>\makebox</literal> command for the picture environment is similar to
the normal <literal>\makebox</literal> command except that you must specify a
<literal>width</literal> and <literal>height</literal> in multiples of <literal>\unitlength</literal>.</para>
        <para>The optional argument, <literal>[position]</literal>, specifies the quadrant that
your text appears in.  You may select up to two of the following:</para>
        <itemizedlist mark="bullet">
          <listitem>
            <para><literal>t</literal> - Moves the item to the top of the rectangle</para>
          </listitem>
          <listitem>
            <para><literal>b</literal> - Moves the item to the bottom</para>
          </listitem>
          <listitem>
            <para><literal>l</literal> - Moves the item to the left</para>
          </listitem>
          <listitem>
            <para><literal>r</literal> - Moves the item to the right</para>
          </listitem>
        </itemizedlist>
        <para>See <xref linkend="\makebox"></xref>.</para>
      </sect2>

      <sect2 label="8.18.3" id="\framebox-(picture)">
        <title><literal>\framebox</literal></title>
        <para><indexterm role="fn"><primary>\framebox</primary></indexterm>
Synopsis:</para>
        <screen>
\framebox(<replaceable>width</replaceable>,<replaceable>height</replaceable>)[<replaceable>pos</replaceable>]{...}
</screen>
        <para>The <literal>\framebox</literal> command is like <literal>\makebox</literal> (see previous
section), except that it puts a frame around the outside of the box
that it creates.</para>
        <para><indexterm role="fn"><primary>\fboxrule</primary></indexterm><indexterm role="fn"><primary>\fboxsep</primary></indexterm>The <literal>\framebox</literal> command produces a rule of thickness
<literal>\fboxrule</literal>, and leaves a space <literal>\fboxsep</literal> between the rule
and the contents of the box.</para>
      </sect2>

      <sect2 label="8.18.4" id="\dashbox">
        <title><literal>\dashbox</literal></title>
        <para><indexterm role="fn"><primary>\dashbox</primary></indexterm>
Draws a box with a dashed line.  Synopsis:</para>
        <screen>
\dashbox{<replaceable>dlen</replaceable>}(<replaceable>rwidth</replaceable>,<replaceable>rheight</replaceable>)[<replaceable>pos</replaceable>]{<replaceable>text</replaceable>}
</screen>
        <para><literal>\dashbox</literal> creates a dashed rectangle around <replaceable>text</replaceable> in a
<literal>picture</literal> environment.  Dashes are <replaceable>dlen</replaceable> units long, and the
rectangle has overall width <replaceable>rwidth</replaceable> and height <replaceable>rheight</replaceable>.
The <replaceable>text</replaceable> is positioned at optional <replaceable>pos</replaceable>.  
<!-- xxref positions. -->
A dashed box looks best when the <literal>rwidth</literal> and <literal>rheight</literal> are
multiples of the <literal>dlen</literal>.</para>
      </sect2>

      <sect2 label="8.18.5" id="\frame">
        <title><literal>\frame</literal></title>
        <para><indexterm role="fn"><primary>\frame</primary></indexterm>
Synopsis:</para>
        <screen>
\frame{<replaceable>text</replaceable>}
</screen>
        <para>The <literal>\frame</literal> command puts a rectangular frame around <replaceable>text</replaceable>.
The reference point is the bottom left corner of the frame.  No extra
space is put between the frame and the object.</para>
      </sect2>

      <sect2 label="8.18.6" id="\line">
        <title><literal>\line</literal></title>
        <para><indexterm role="fn"><primary>\line</primary></indexterm>
Synopsis:</para>
        <screen>
\line(<replaceable>xslope</replaceable>,<replaceable>yslope</replaceable>){<replaceable>length</replaceable>}
</screen>
        <para>The <literal>\line</literal> command draws a line with the given <replaceable>length</replaceable> and
slope <replaceable>xslope</replaceable>/<replaceable>yslope</replaceable>.</para>
        <para>Standard &latex; can only draw lines with <replaceable>slope</replaceable> = x/y,
where x and y have integer values from &minus;6
through&#xa0;6.  For lines of any slope, not to mention other shapes,
see the <literal>curve2e</literal> and many many other packages on CTAN.</para>
      </sect2>

      <sect2 label="8.18.7" id="\linethickness">
        <title><literal>\linethickness</literal></title>
        <para><indexterm role="fn"><primary>\linethickness</primary></indexterm>
The <literal>\linethickness{<replaceable>dim</replaceable>}</literal> command declares the thickness
of horizontal and vertical lines in a picture environment to be
<replaceable>dim</replaceable>, which must be a positive length.</para>
        <para><literal>\linethickness</literal> does not affect the thickness of slanted lines,
circles, or the quarter circles drawn by <literal>\oval</literal>.</para>
      </sect2>

      <sect2 label="8.18.8" id="\thicklines">
        <title><literal>\thicklines</literal></title>
        <para><indexterm role="fn"><primary>\thicklines</primary></indexterm>
The <literal>\thicklines</literal> command is an alternate line thickness for
horizontal and vertical lines in a picture environment;
cf.&#xa0;<xref linkend="\linethickness"></xref> and <xref linkend="\thinlines"></xref>.</para>
      </sect2>

      <sect2 label="8.18.9" id="\thinlines">
        <title><literal>\thinlines</literal></title>
        <para><indexterm role="fn"><primary>\thinlines</primary></indexterm>
The <literal>\thinlines</literal> command is the default line thickness for
horizontal and vertical lines in a picture environment;
cf.&#xa0;<xref linkend="\linethickness"></xref> and <xref linkend="\thicklines"></xref>.</para>
      </sect2>

      <sect2 label="8.18.10" id="\multiput">
        <title><literal>\multiput</literal></title>
        <para><indexterm role="fn"><primary>\multiput</primary></indexterm>
Synopsis:</para>
        <screen>
\multiput(<replaceable>x</replaceable>,<replaceable>y</replaceable>)(<replaceable>delta_x</replaceable>,<replaceable>delta_y</replaceable>){<replaceable>n</replaceable>}{<replaceable>obj</replaceable>}
</screen>
        <para>The <literal>\multiput</literal> command copies the object <replaceable>obj</replaceable> in a regular
pattern across a picture.  <replaceable>obj</replaceable> is first placed at position
(x,y), then at (x+\delta x,y+\delta y), and so on,
<replaceable>n</replaceable> times.</para>
      </sect2>

      <sect2 label="8.18.11" id="\oval">
        <title><literal>\oval</literal></title>
        <para><indexterm role="fn"><primary>\oval</primary></indexterm>
Synopsis:</para>
        <screen>
\oval(<replaceable>width</replaceable>,<replaceable>height</replaceable>)[<replaceable>portion</replaceable>]
</screen>
        <para>The <literal>\oval</literal> command produces a rectangle with rounded corners.
The optional argument <replaceable>portion</replaceable> allows you to select part of the
oval via the following:</para>
        <variablelist>
          <varlistentry>
            <term><literal>t</literal></term>
            <listitem>
              <para>selects the top portion;</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>b</literal></term>
            <listitem>
              <para>selects the bottom portion;</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>r</literal></term>
            <listitem>
              <para>selects the right portion;</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>l</literal></term>
            <listitem>
              <para>selects the left portion.</para>
            </listitem>
          </varlistentry>
        </variablelist>
        <para>The &ldquo;corners&rdquo; of the oval are made with quarter circles with a
maximum radius of 20pt, so large &ldquo;ovals&rdquo; will look more like
boxes with rounded corners.</para>
      </sect2>

      <sect2 label="8.18.12" id="\put">
        <title><literal>\put</literal></title>
        <para><indexterm role="fn"><primary>\put</primary></indexterm>
<literal>\put(x coord,y coord){ ...  }</literal></para>
        <para>The <literal>\put</literal> command places the item specified by the mandatory
argument at the given coordinates.</para>
      </sect2>

      <sect2 label="8.18.13" id="\shortstack">
        <title><literal>\shortstack</literal></title>
        <para><indexterm role="fn"><primary>\shortstack</primary></indexterm>
Synopsis:</para>
        <screen>
\shortstack[<replaceable>position</replaceable>]{...\\...\\...}
</screen>
        <para>The <literal>\shortstack</literal> command produces a stack of objects.  The valid
positions are:</para>
        <variablelist>
          <varlistentry>
            <term><literal>r</literal></term>
            <listitem>
              <para>Move the objects to the right of the stack.</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>l</literal></term>
            <listitem>
              <para>Move the objects to the left of the stack</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>c</literal></term>
            <listitem>
              <para>Move the objects to the centre of the stack (default)</para>
            </listitem>
          </varlistentry>
        </variablelist>
        <para><indexterm role="fn"><primary>\\ (for <literal>\shortstack</literal> objects)</primary></indexterm>Objects are separated with <literal>\\</literal>.</para>
      </sect2>

      <sect2 label="8.18.14" id="\vector">
        <title><literal>\vector</literal></title>
        <para><indexterm role="fn"><primary>\vector</primary></indexterm>
Synopsis:</para>
        <screen>
\vector(<replaceable>x-slope</replaceable>,<replaceable>y-slope</replaceable>){<replaceable>length</replaceable>}
</screen>
        <para>The <literal>\vector</literal> command draws a line with an arrow of the specified
length and slope.  The x and y values must lie between
&minus;4 and +4, inclusive.</para>
      </sect2>
    </sect1>

    <sect1 label="8.19" id="quotation">
      <title><literal>quotation</literal></title>
      <para><indexterm role="fn"><primary>quotation</primary></indexterm><indexterm role="cp"><primary>quoted text with paragraph indentation, displaying</primary></indexterm><indexterm role="cp"><primary>displaying quoted text with paragraph indentation</primary></indexterm><indexterm role="cp"><primary>paragraph indentations in quoted text</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{quotation}
<replaceable>text</replaceable>
\end{quotation}
</screen>
      <para>The margins of the <literal>quotation</literal> environment are indented on both
the left and the right.  The text is justified at both margins.
Leaving a blank line between text produces a new paragraph.</para>
      <para>Unlike the <literal>quote</literal> environment, each paragraph is indented
normally.</para>
    </sect1>

    <sect1 label="8.20" id="quote">
      <title><literal>quote</literal></title>
      <para><indexterm role="fn"><primary>quote</primary></indexterm><indexterm role="cp"><primary>quoted text without paragraph indentation, displaying</primary></indexterm><indexterm role="cp"><primary>displaying quoted text without paragraph indentation</primary></indexterm><indexterm role="cp"><primary>paragraph indentations in quoted text, omitting</primary></indexterm>
Snyopsis:</para>
      <screen>
\begin{quote}
<replaceable>text</replaceable>
\end{quote}
</screen>
      <para>The margins of the <literal>quote</literal> environment are indented on both the
left and the right.  The text is justified at both margins.  Leaving a
blank line between text produces a new paragraph.</para>
      <para>Unlike the <literal>quotation</literal> environment, paragraphs are not indented.</para>
    </sect1>

    <sect1 label="8.21" id="tabbing">
      <title><literal>tabbing</literal></title>
      <para><indexterm role="fn"><primary>tabbing environment</primary></indexterm><indexterm role="cp"><primary>tab stops, using</primary></indexterm><indexterm role="cp"><primary>lining text up in columns using tab stops</primary></indexterm><indexterm role="cp"><primary>alignment via tabbing</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{tabbing}
<replaceable>row1col1</replaceable> \= <replaceable>row1col2</replaceable> \= <replaceable>row1col3</replaceable> \= <replaceable>row1col4</replaceable> \\
<replaceable>row2col1</replaceable> \&gt;                \&gt; <replaceable>row2col3</replaceable> \\
...
\end{tabbing}
</screen>
      <para>The <literal>tabbing</literal> environment provides a way to align text in
columns.  It works by setting tab stops and tabbing to them much as
was done on an ordinary typewriter.  It is best suited for cases where
the width of each column is constant and known in advance.</para>
      <para>This environment can be broken across pages, unlike the <literal>tabular</literal>
environment.</para>
      <para>The following commands can be used inside a <literal>tabbing</literal> enviroment:</para>
      <variablelist>
        <varlistentry>
          <term><literal>\\ tabbing</literal></term>
          <listitem>
            <para>End a line.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\= (tabbing)</literal></term>
          <listitem>
            <para>Sets a tab stop at the current position.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\&gt; (tabbing)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\&gt;</primary></indexterm>Advances to the next tab stop.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\&lt;</literal></term>
          <listitem>
            <para>Put following text to the left of the local margin (without changing
the margin).  Can only be used at the start of the line.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\+</literal></term>
          <listitem>
            <para>Moves the left margin of the next and all the
following commands one tab stop to the right, beginning tabbed line if
necessary.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\-</literal></term>
          <listitem>
            <para>Moves the left margin of the next and all the
following commands one tab stop to the left, beginning tabbed line if
necessary.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\' (tabbing)</literal></term>
          <listitem>
            <para>Moves everything that you have typed so far in the
current column, i.e. everything from the most recent <literal>\&gt;</literal>,
<literal>\&lt;</literal>, <literal>\'</literal>, <literal>\\</literal>, or <literal>\kill</literal> command, to the right
of the previous column, flush against the current column's tab stop.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\` (tabbing)</literal></term>
          <listitem>
            <para>Allows you to put text flush right against any tab stop, including tab
stop&#xa0;0.  However, it can't move text to the right of the last column
because there's no tab stop there.  The <literal>\`</literal> command moves all the
text that follows it, up to the <literal>\\</literal> or <literal>\end{tabbing}</literal>
command that ends the line, to the right margin of the tabbing
environment.  There must be no <literal>\&gt;</literal> or <literal>\'</literal> command between
the <literal>\`</literal> and the command that ends the line.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\a (tabbing)</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\a' (acute accent in tabbing)</primary></indexterm><indexterm role="fn"><primary>\a` (grave accent in tabbing)</primary></indexterm><indexterm role="fn"><primary>\a= (macron accent in tabbing)</primary></indexterm>In a <literal>tabbing</literal> environment, the commands <literal>\=</literal>, <literal>\'</literal> and
<literal>\`</literal> do not produce accents as usual (see <xref linkend="Accents"></xref>).  Instead,
the commands <literal>\a=</literal>, <literal>\a'</literal> and <literal>\a`</literal> are used.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\kill</literal></term>
          <listitem>
            <para>Sets tab stops without producing text.  Works just like <literal>\\</literal>
except that it throws away the current line instead of producing
output for it.  The effect of any <literal>\=</literal>, <literal>\+</literal> or <literal>\-</literal>
commands in that line remain in effect.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\poptabs</literal></term>
          <listitem>
            <para><indexterm role="fn"><primary>\poptabs</primary></indexterm>Restores the tab stop positions saved by the last <literal>\pushtabs</literal>.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\pushtabs</literal></term>
          <listitem>
            <para>Saves all current tab stop positions. Useful for temporarily changing
tab stop positions in the middle of a <literal>tabbing</literal> environment.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\tabbingsep</literal></term>
          <listitem>
            <para>Distance to left of tab stop moved by <literal>\'</literal>.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>This example typesets a Pascal function in a traditional format:</para>
      <screen>
\begin{tabbing}
function \= fact(n : integer) : integer;\\
         \&gt; begin \= \+ \\
               \&gt; if \= n $&gt;$ 1 then \+ \\
                        fact := n * fact(n-1) \- \\
                  else \+ \\
                        fact := 1; \-\- \\
            end;\\
\end{tabbing}
</screen>
    </sect1>

    <sect1 label="8.22" id="table">
      <title><literal>table</literal></title>
      <para><indexterm role="fn"><primary>table</primary></indexterm><indexterm role="cp"><primary>tables, creating</primary></indexterm><indexterm role="cp"><primary>creating tables</primary></indexterm>
Synopsis:</para>
      <screen>
 \begin{table}[placement]

  body of the table

 \caption{table title}
 \end{table}
</screen>
      <para>Tables are objects that are not part of the normal text, and are
usually &ldquo;floated&rdquo; to a convenient place, like the top of a page.
Tables will not be split between two pages.</para>
      <para>The optional argument <literal>[placement]</literal> determines where &latex; will try
to place your table.  There are four places where &latex; can possibly put
a float:</para>
      <itemizedlist mark="bullet">
        <listitem>
          <para><literal>h</literal>: Here - at the position in the text where the table
environment appears.</para>
        </listitem>
        <listitem>
          <para><literal>t</literal>: Top - at the top of a text page.</para>
        </listitem>
        <listitem>
          <para><literal>b</literal>: Bottom - at the bottom of a text page.</para>
        </listitem>
        <listitem>
          <para><literal>p</literal>: Page of floats - on a separate float page, which is a page
containing no text, only floats.</para>
        </listitem>
      </itemizedlist>
      <para>The standard <literal>report</literal> and <literal>article</literal> classes use the default
placement <literal>[tbp]</literal>.</para>
      <para>The body of the table is made up of whatever text, &latex; commands, etc.,
you wish.  The <literal>\caption</literal> command allows you to title your table.</para>
    </sect1>

    <sect1 label="8.23" id="tabular">
      <title><literal>tabular</literal></title>
      <para><indexterm role="fn"><primary>tabular environment</primary></indexterm><indexterm role="cp"><primary>lines in tables</primary></indexterm><indexterm role="cp"><primary>lining text up in tables</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{tabular}[pos]{cols}
column 1 entry &amp; column 2 entry ... &amp; column n entry \\
...
\end{tabular}
</screen>        
      <para>or</para>
      <screen>
\begin{tabular*}{width}[pos]{cols}
column 1 entry &amp; column 2 entry ... &amp; column n entry \\
...
\end{tabular*}
</screen>
      <para>These environments produce a box consisting of a sequence of rows of
items, aligned vertically in columns.</para>
      <para><indexterm role="fn"><primary>\\ for <literal>tabular</literal></primary></indexterm><literal>\\</literal> must be used to specify the end of each row of the table,
except for the last, where it is optional&mdash;unless an <literal>\hline</literal>
command (to put a rule below the table) follows.</para>
      <para>The mandatory and optional arguments consist of:</para>
      <variablelist>
        <varlistentry>
          <term><literal>width</literal></term>
          <listitem>
            <para>Specifies the width of the <literal>tabular*</literal> environment.  There must be
rubber space between columns that can stretch to fill out the specified
width.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>pos</literal></term>
          <listitem>
            <para>Specifies the vertical position; default is alignment on the centre of
the environment.</para>
            <itemizedlist mark="bullet">
              <listitem>
                <para><literal>t</literal> - align on top row</para>
              </listitem>
              <listitem>
                <para><literal>b</literal> - align on bottom row</para>
              </listitem>
            </itemizedlist>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>cols</literal></term>
          <listitem>
            <para>Specifies the column formatting.  It consists of a sequence of the
following specifiers, corresponding to the sequence of columns and
intercolumn material.</para>
            <itemizedlist mark="bullet">
              <listitem>
                <para><literal>l</literal> - A column of left-aligned items.</para>
              </listitem>
              <listitem>
                <para><literal>r</literal> - A column of right-aligned items.</para>
              </listitem>
              <listitem>
                <para><literal>c</literal> - A column of centred items.</para>
              </listitem>
              <listitem>
                <para><literal>|</literal> - A vertical line the full height and depth of the environment.</para>
              </listitem>
              <listitem>
                <para><literal>@{text}</literal> - This inserts <literal>text</literal> in every row.  An @-expression
suppresses the intercolumn space normally inserted between columns; any
desired space between the inserted text and the adjacent items must be
included in text.  An <literal>\extracolsep{wd}</literal> command in an
@-expression causes an extra space of width <literal>wd</literal> to appear to the
left of all subsequent columns, until countermanded by another
<literal>\extracolsep</literal> command.  Unlike ordinary intercolumn space, this
extra space is not suppressed by an @-expression.  An
<literal>\extracolsep</literal> command can be used only in an @-expression in the
<literal>cols</literal> argument.</para>
              </listitem>
              <listitem>
                <para><literal>p{wd}</literal> - Produces a column with each item typeset in a parbox of
width <literal>wd</literal>, as if it were the argument of a <literal>\parbox[t]{wd}</literal>
command.  However, a <literal>\\</literal> may not appear in the item, except in the
following situations:</para>
                <orderedlist numeration="arabic">
                  <listitem>
                    <para>inside an environment like <literal>minipage</literal>, <literal>array</literal>, or <literal>tabular</literal>.</para>
                  </listitem>
                  <listitem>
                    <para>inside an explicit <literal>\parbox</literal>.</para>
                  </listitem>
                  <listitem>
                    <para>in the scope of a <literal>\centering</literal>, <literal>\raggedright</literal>, or <literal>\raggedleft</literal>
declaration.  The latter declarations must appear inside braces or an
environment when used in a <literal>p</literal>-column element.</para>
                  </listitem>
                </orderedlist>
              </listitem>
              <listitem>
                <para><literal>*{num}{cols}</literal> - Equivalent to <literal>num</literal> copies of
<literal>cols</literal>, where <literal>num</literal> is any positive integer and <literal>cols</literal> is
any list of column-specifiers, which may contain another
<literal>*-expression</literal>.</para>
              </listitem>
            </itemizedlist>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>Parameters that control formatting:
<!-- xx defaults, own node (xref from array)? --></para>
      <variablelist>
        <varlistentry>
          <term><literal>\arrayrulewidth</literal></term>
          <listitem>
            <para>Thickness of the rule created by <literal>|</literal>, <literal>\hline</literal>, and
<literal>\vline</literal> in the <literal>tabular</literal> and <literal>array</literal> environments; the
default is &lsquo;<literal>.4pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\arraystretch</literal></term>
          <listitem>
            <para>Scaling of spacing between rows in the <literal>tabular</literal> and <literal>array</literal>
environments; default is &lsquo;<literal>1</literal>&rsquo;,for no scaling.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\doublerulesep</literal></term>
          <listitem>
            <para>Horizontal distance between the vertical rules produced by <literal>||</literal>
in the <literal>tabular</literal> and <literal>array</literal> environments; default is &lsquo;<literal>2pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
        <varlistentry>
          <term><literal>\tabcolsep</literal></term>
          <listitem>
            <para>Half the width of the space between columns; default is &lsquo;<literal>6pt</literal>&rsquo;.</para>
          </listitem>
        </varlistentry>
      </variablelist>
      <para>These commands can be used inside a <literal>tabular</literal> environment:</para>

      <sect2 label="8.23.1" id="\multicolumn">
        <title><literal>\multicolumn</literal></title>
        <para><indexterm role="fn"><primary>\multicolumn</primary></indexterm>
Synopsis:</para>
        <screen>
\multicolumn{<replaceable>cols</replaceable>}{<replaceable>pos</replaceable>}{<replaceable>text</replaceable>}
</screen>
        <para>The <literal>\multicolumn</literal> command makes an entry that spans several
columns.  The first mandatory argument, <replaceable>cols</replaceable>, specifies the
number of columns to span.  The second mandatory argument, <replaceable>pos</replaceable>,
specifies the formatting of the entry; <literal>c</literal> for centered, <literal>l</literal>
for flushleft, <literal>r</literal> for flushright.  The third mandatory argument,
<replaceable>text</replaceable>, specifies what text to put in the entry.</para>
        <para>Here's an example showing two columns separated by an en-dash;
<literal>\multicolumn</literal> is used for the heading:</para>
        <screen>
\begin{tabular}{r@{--}l}
\multicolumn{2}{c}{\bf Unicode}\cr
   0x80&amp;0x7FF   \cr
  0x800&amp;0xFFFF  \cr
0x10000&amp;0x1FFFF \cr
\end{tabular}
</screen>
      </sect2>

      <sect2 label="8.23.2" id="\cline">
        <title><literal>\cline</literal></title>
        <para><indexterm role="fn"><primary>\cline</primary></indexterm>
Synopsis:</para>
        <screen>
\cline{<replaceable>i</replaceable>-<replaceable>j</replaceable>}
</screen>
        <para>The <literal>\cline</literal> command draws horizontal lines across the columns
specified, beginning in column <replaceable>i</replaceable> and ending in column <replaceable>j</replaceable>,
which are specified in the mandatory argument.</para>
      </sect2>

      <sect2 label="8.23.3" id="\hline">
        <title><literal>\hline</literal></title>
        <para><indexterm role="fn"><primary>\hline</primary></indexterm>
The <literal>\hline</literal> command draws a horizontal line the width of the
enclosing <literal>tabular</literal> or <literal>array</literal> environment.  It's most
commonly used to draw a line at the top, bottom, and between the rows
of a table.</para>
      </sect2>

      <sect2 label="8.23.4" id="\vline">
        <title><literal>\vline</literal></title>
        <para><indexterm role="fn"><primary>\vline</primary></indexterm>
The <literal>\vline</literal> command will draw a vertical line extending the full
height and depth of its row.  An <literal>\hfill</literal> command can be used to
move the line to the edge of the column.  It can also be used in an
@-expression.</para>
      </sect2>
    </sect1>

    <sect1 label="8.24" id="thebibliography">
      <title><literal>thebibliography</literal></title>
      <para><indexterm role="fn"><primary>thebibliography</primary></indexterm><indexterm role="cp"><primary>bibliography, creating (manually)</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{thebibliography}{<replaceable>widest-label</replaceable>}
\bibitem[<replaceable>label</replaceable>]{<replaceable>cite_key}</replaceable>
...
\end{thebibliography}
</screen>
      <para>The <literal>thebibliography</literal> environment produces a bibliography or
reference list.</para>
      <para>In the <literal>article</literal> class, this reference list is labelled
&ldquo;References&rdquo;; in the <literal>report</literal> class, it is labelled
&ldquo;Bibliography&rdquo;.  You can change the label (in the standard classes)
by redefining the command <literal>\refname</literal>.  For instance, this
eliminates it entirely:</para>
      <screen>
\renewcommand{\refname}{}
</screen>
      <para>The mandatory <replaceable>widest-label</replaceable> argument is text that, when typeset,
is as wide as the widest item label produced by the <literal>\bibitem</literal>
commands.  It is typically given as <literal>9</literal> for bibliographies with
less than 10 references, <literal>99</literal> for ones with less than 100, etc.</para>

      <sect2 label="8.24.1" id="\bibitem">
        <title><literal>\bibitem</literal></title>
        <para><indexterm role="fn"><primary>\bibitem</primary></indexterm>
Synopsis:</para>
        <screen>
\bibitem[<replaceable>label</replaceable>]{<replaceable>cite_key</replaceable>}
</screen>
        <para>The <literal>\bibitem</literal> command generates an entry labelled by
<replaceable>label</replaceable>.  If the <replaceable>label</replaceable> argument is missing, a number is
automatically generated using the <literal>enumi</literal> counter.  The
<replaceable>cite_key</replaceable> is any sequence of letters, numbers, and punctuation
symbols not containing a comma.</para>
        <para>This command writes an entry to the <filename>.aux</filename> file containing the
item's <replaceable>cite_key</replaceable> and label.  When the <filename>.aux</filename> file is read by
the <literal>\begin{document}</literal> command, the item's <literal>label</literal> is
associated with <literal>cite_key</literal>, causing references to <replaceable>cite_key</replaceable>
with a <literal>\cite</literal> command (see next section) to produce the
associated label.</para>
      </sect2>

      <sect2 label="8.24.2" id="\cite">
        <title><literal>\cite</literal></title>
        <para><indexterm role="fn"><primary>\cite</primary></indexterm>
Synopsis:</para>
        <screen>
\cite[<replaceable>subcite</replaceable>]{<replaceable>keys</replaceable>
</screen>
        <para>The <replaceable>keys</replaceable> argument is a list of one or more citation keys,
separated by commas.  This command generates an in-text citation to
the references associated with <replaceable>keys</replaceable> by entries in the
<filename>.aux</filename> file.</para>
        <para>The text of the optional <replaceable>subcite</replaceable> argument appears after the
citation.  For example, <literal>\cite[p.~314]{knuth}</literal> might produce
`[Knuth, p.&#xa0;314]'.</para>
      </sect2>

      <sect2 label="8.24.3" id="\nocite">
        <title><literal>\nocite</literal></title>
        <para><indexterm role="fn"><primary>\nocite</primary></indexterm>
<literal>\nocite{key_list}</literal></para>
        <para>The <literal>\nocite</literal> command produces no text, but writes <literal>key_list</literal>,
which is a list of one or more citation keys, on the <filename>.aux</filename> file.</para>
      </sect2>

      <sect2 label="8.24.4" id="Using-BibTeX">
        <title>Using Bib&tex;</title>
        <para><indexterm role="cp"><primary>using Bib&tex;</primary></indexterm><indexterm role="cp"><primary>bib&tex;, using</primary></indexterm><indexterm role="cp"><primary>bibliography, creating (automatically)</primary></indexterm><indexterm role="fn"><primary>\bibliographystyle</primary></indexterm><indexterm role="fn"><primary>\bibliography</primary></indexterm>
If you use the Bib&tex; program by Oren Patashnik (highly
recommended if you need a bibliography of more than a couple of
titles) to maintain your bibliography, you don't use the
<literal>thebibliography</literal> environment (see <xref linkend="thebibliography"></xref>). Instead,
you include the lines</para>
        <screen>
\bibliographystyle{<replaceable>bibstyle</replaceable>}
\bibliography{<replaceable>bibfile1</replaceable>,<replaceable>bibfile2</replaceable>}
</screen>
        <para>The <literal>\bibliographystyle</literal> command does not produce any output of
its own.  Rather, it defines the style in which the bibliography will
be produced: <replaceable>bibstyle</replaceable> refers to a file
<replaceable>bibstyle</replaceable><filename>.bst</filename>, which defines how your citations will look.
The standard <replaceable>style</replaceable> names distributed with Bib&tex; are:</para>
        <variablelist>
          <varlistentry>
            <term><literal>alpha</literal></term>
            <listitem>
              <para>Sorted alphabetically. Labels are formed from name of author and year of
publication.</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>plain</literal></term>
            <listitem>
              <para>Sorted alphabetically. Labels are numeric.</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>unsrt</literal></term>
            <listitem>
              <para>Like <literal>plain</literal>, but entries are in order of citation.</para>
            </listitem>
          </varlistentry>
          <varlistentry>
            <term><literal>abbrv</literal></term>
            <listitem>
              <para>Like <literal>plain</literal>, but more compact labels.</para>
            </listitem>
          </varlistentry>
        </variablelist>
        <para>In addition, numerous other Bib&tex; style files exist tailored to
the demands of various publications.  See
<ulink url="http://www.ctan.org/tex-archive/biblio/bibtex/contrib">http://www.ctan.org/tex-archive/biblio/bibtex/contrib</ulink>.</para>
        <para>The <literal>\bibliography</literal> command is what actually produces the
bibliography.  The argument to <literal>\bibliography</literal> refers to files
named <filename><replaceable>bibfile</replaceable>.bib</filename>, which should contain your database in
Bib&tex; format.  Only the entries referred to via <literal>\cite</literal> and
<literal>\nocite</literal> will be listed in the bibliography.</para>
      </sect2>
    </sect1>

    <sect1 label="8.25" id="theorem">
      <title><literal>theorem</literal></title>
      <para><indexterm role="fn"><primary>theorem environment</primary></indexterm><indexterm role="cp"><primary>theorems, typesetting</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{theorem}
<replaceable>theorem-text</replaceable>
\end{theorem}
</screen>
      <para>The <literal>theorem</literal> environment produces &ldquo;Theorem <replaceable>n</replaceable>&rdquo; in
boldface followed by <replaceable>theorem-text</replaceable>, where the numbering
possibilities for <replaceable>n</replaceable> are described under <literal>\newtheorem</literal>
(see <xref linkend="\newtheorem"></xref>).</para>
    </sect1>

    <sect1 label="8.26" id="titlepage">
      <title><literal>titlepage</literal></title>
      <para><indexterm role="fn"><primary>titlepage environment</primary></indexterm><indexterm role="cp"><primary>making a title page</primary></indexterm><indexterm role="cp"><primary>title pages, creating</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{titlepage}
<replaceable>text</replaceable>
\end{titlepage}
</screen>
      <para>The <literal>titlepage</literal> environment creates a title page, i.e., a page
with no printed page number or heading.  It also causes the following
page to be numbered page one.  Formatting the title page is left to
you.  The <literal>\today</literal> command may be useful on title pages
(see <xref linkend="\today"></xref>).</para>
      <para>You can use the <literal>\maketitle</literal> command (see <xref linkend="\maketitle"></xref>) to
produce a standard title page without a <literal>titlepage</literal> environment.</para>
    </sect1>

    <sect1 label="8.27" id="verbatim">
      <title><literal>verbatim</literal></title>
      <para><indexterm role="fn"><primary>verbatim environment</primary></indexterm><indexterm role="cp"><primary>verbatim text</primary></indexterm><indexterm role="cp"><primary>simulating typed text</primary></indexterm><indexterm role="cp"><primary>typed text, simulating</primary></indexterm><indexterm role="cp"><primary>code, typesetting</primary></indexterm><indexterm role="cp"><primary>computer programs, typesetting</primary></indexterm>
Synopsis:</para>
      <screen>
\begin{verbatim}
<replaceable>literal-text</replaceable>
\end{verbatim}
</screen>
      <para>The <literal>verbatim</literal> environment is a paragraph-making environment in
which &latex; produces exactly what you type in; for instance the
<literal>\</literal> character produces a printed &lsquo;<literal>\</literal>&rsquo;.  It turns &latex;
into a typewriter with carriage returns and blanks having the same
effect that they would on a typewriter.</para>
      <para>The <literal>verbatim</literal> uses a monospaced typewriter-like font (<literal>\tt</literal>).</para>

      <sect2 label="8.27.1" id="\verb">
        <title><literal>\verb</literal></title>
        <para><indexterm role="fn"><primary>\verb</primary></indexterm><indexterm role="cp"><primary>verbatim text, inline</primary></indexterm>
Synopsis:</para>
      