% \iffalse meta-comment
%
% Copyright (C) 1993-2024
% The LaTeX Project and any individual authors listed elsewhere
% in this file.
%
% This file is part of the LaTeX base system.
% -------------------------------------------
%
% It may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either version 1.3c
% of this license or (at your option) any later version.
% The latest version of this license is in
%    https://www.latex-project.org/lppl.txt
% and version 1.3c or later is part of all distributions of LaTeX
% version 2008 or later.
%
% This file has the LPPL maintenance status "maintained".
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% information.
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% The list of derived (unpacked) files belonging to the distribution
% and covered by LPPL is defined by the unpacking scripts (with
% extension .ins) which are part of the distribution.
%
% \fi
%
% \iffalse
% Copyright (C) 1994-97 LaTeX Project, Frank Mittelbach
% and Rainer Sch\"opf, all rights reserved.
%
%    \begin{macrocode}
%<+class>\NeedsTeXFormat{LaTeX2e}[1997/06/01]
%    \end{macrocode}
%
%    Announce the Class name and its version:
% \changes{v2.3b}{1994/05/01}{Removed the use of \cs{fileversion}
%    c.s.}
% \changes{v2.3b}{1994/05/01}{Added \cs{ProvidesFile} to slides.def.}
% \changes{v2.3o}{1995/05/17}{Replaced all \cs{hbox to} with
%    \cs{hb@xt@}.}
% \changes{v2.3o}{1995/05/17}{Cleaned up the \cs{changes} entries.}
% \changes{v2.3p}{1995/05/23}{Corrected some brace mismatches.}
% \changes{v2.3q}{1995/09/20}{Replaced \cs{@tempa} by \cs{reserved@a}.}
% \changes{v2.3r}{1995/09/27}{Globally replaced scale factor 19.91 by
%          19.907 in \cs{DeclareFontShape}, as this gives better
%          rounded font sizes at 600dpi (suggested by Denis Roegel).}
%    \begin{macrocode}
%<+class>\ProvidesClass{slides}
%<+cmd>\ProvidesFile{slides.def}
%<*driver>
       \ProvidesFile{slides.drv}
%</driver>
              [2022/05/18 v2.4b
%<+class>               Standard LaTeX document class]
%<+cmd>               SLiTeX definitions]
%    \end{macrocode}
%
% \section{A driver for this document}
%
% \changes{v2.3f}{1994/05/26}{Moved the driver to the front of the
%    file; it doesn't print any longer}
%
% The next bit of code contains the documentation driver file for
% \TeX{}, i.e., the file that will produce the documentation you are
% currently reading. It can be extracted from this file by the
% \dst{} program.
%    \begin{macrocode}
%<*driver>
]
\documentclass{ltxdoc}
%    \end{macrocode}
%    The following command retrieves the date and version information
%    from the file.
%    \begin{macrocode}
\GetFileInfo{slides.drv}
%    \end{macrocode}
%    Some commonly used abbreviations:
% \changes{v2.3h}{1994/06/01}{Added definition of \cs{SLiTeX}.}
%    \begin{macrocode}
\DeclareRobustCommand{\SLiTeX}{{%
   \normalfont S\kern -.06em
   {\scshape l\kern -.035emi}\kern -.06em
   \TeX
}}
\newcommand*{\Lopt}[1]{\textsf {#1}}
\newcommand*{\file}[1]{\texttt {#1}}
\newcommand*{\Lcount}[1]{\textsl {\small#1}}
\newcommand*{\pstyle}[1]{\textsl {#1}}
\newcommand*{\dst}{{\normalfont\scshape docstrip}}
%
%    \end{macrocode}
%    Now start the document and input this file.
% \changes{v2.3d}{1994/05/12}{Added a missing \cs{begin\{macrocode\}}}
%    \begin{macrocode}
\begin{document}
   \DocInput{slides.dtx}
\end{document}
%</driver>
%    \end{macrocode}
%\fi
%
%
% \changes{v2.1b}{1993/12/13}{Removed \cs{CodelineIndex} from the
%    driver code.}
% \changes{v2.1e}{1993/12/16}{Removed again different definitions for
%    font commands font commands in non-compatibility mode.}
%
% \changes{v2.2}{1993/12/18}{Changes to make it work with
%    compatibility mode.}
% \changes{v2.2a}{1993/12/19}{Removed float parms}
% \changes{v2.2d}{1994/01/31}{Removed \cs{@normalsize definition}}
% \changes{v2.2g}{1994/03/01}{Removed option makeidx.}
% \changes{v2.2g}{1994/03/01}{Moved driver up front.}
% \changes{v2.2g}{1994/03/01}{Renamed files \file{slides.ltx} and
%    \file{sfontdef.ltx} to \file{slides.def} and \file{sfonts.def}.}
% \changes{v2.2l}{1994/03/16}{Removed \cs{typeouts}}
% \changes{v2.3}{1994/03/16}{Removed root/slide-file structure except
%    for compatibility mode. (LL)}
% \changes{v2.3}{1994/03/16}{Added clock option (LL)}
% \changes{v2.3}{1994/03/16}{Modified slide, overlay, note
%    environments. (LL)}
% \changes{v2.3}{1994/03/16}{Added titlepage option and
%    \cs{maketitle}. (LL)}
% \changes{v2.3c}{1994/05/06}{Changed documentation to use
%    `environment' instead of `macro' environment for environments}
% \changes{v2.3f}{1994/05/26}{Wrapped two long lines}
% \changes{v2.3l}{1994/12/16}{Use \cs{newcommand*} to define commands
%    with an argument}
% \changes{v2.3n}{1995/04/02}{a slight documentation fix (PR 1517)}
%
% \title{Producing slides with \LaTeXe{}}
% \author{Frank Mittelbach}
% \date{\filedate}
%
% \maketitle
% \MaintainedByLaTeXTeam{latex}
%
% \section{Introduction}
%
% With \LaTeXe{} it is now no longer necessary to maintain a special
% format for producing overhead slides. Instead the standard format
% may be used and internally only different font definition files come
% into play.
%
% \section{Usage}
%
% For producing slides you have to use |slides| as the
% document class. This class is very similar to the |slides| style
% that came with \SliTeX{}, in fact it is basically a copy changed to
% work under \LaTeXe{}.\footnote{Therefore you should compare the
% new class with old \SliTeX{} styles
% in case you have local slide classes to see what you have to change
% in order to use them with \LaTeXe{}.} Thus you have to say something
% like
% \begin{verbatim}
%   \documentclass[...]{slides}
% \end{verbatim}
% and process this with \LaTeXe.
%
% \section{Fonts}
%
% Note, that with NFSS you can easily produce slides with special
% fonts just by calling an appropriate style file (like |times|) in a
% |\usepackage| command. This works, for example, with all
% fonts that are defined to be scaleable (e.g., PostScript fonts) since
% they can be used at any size by NFSS.
%
% However, packages like |pandora| won't work because the standard
% |.fd| files shipped with NFSS only contain small sizes. You can, of
% course, produce additional sizes and change the |.fd| files
% accordingly so that they would be useable for slides as well.
%
% \section{Invisible text and color separation}
%
% In the original \SliTeX{} it was possible to produce invisible text
% using the |\invisible| command, so that one was able to put several
% slides on top of each other (with each slides showing additional
% details, etc.). It was also possible to produce `color' slides. This
% was done by producing individual slides one for each color and
% placing them on top of each other.
%
% The availability of color printers and the |color| package make
% color separation obsolete, so it has been removed.  Although the
% |color| has also made |\invisible| obsolete, the command is
% retained in the \LaTeXe{} implementation, but there
% are a few restrictions. Invisible fonts are implemented as special
% shapes where the shape names are build by prefixing the normal shape
% name with an uppercase |I|. For example, the `normal invisible
% shape' would be |In|. When \LaTeX{} is requested to typeset
% invisible it will thus change the current shape attribute in this
% manner. To make this work it is necessary that the resulting font
% shape group is defined. If not, the normal font substitution
% mechanism of \LaTeXe{} will change the attribute until it finds a
% usable font shape group with the result that the text may become
% visible.
%
% As long as you use the standard fonts for slides this is not a
% problem because all the visible font shape groups have invisible
% counterparts. However, if you decide on using special fonts, e.g.,
% PostScript fonts, your |\DeclareFontShape| settings may not contain
% invisible font shape groups and thus you may be unable to use these
% features without adding additional |\DeclareFontShape| commands to
% your |.fd| files or the preamble of your document.
%
% \MaybeStop{}
%
%
% \section{The Implementation}
%
% \begin{quote}
% \textbf{Warning:} The implementation is still very experimental and
% may change internally very much. It currently basically consists of a
% slightly modified copy of |slides.sty| (which then forms
% |slides.cls|) followed by a slightly changed copy of |slitex.tex|.
% Documentation is practically
% non-existing.  Everybody is invited to help changing this!
% \end{quote}
%
% The code is divided into two parts, we first implement the class
% related functions and declarations and then define low level stuff
% that is necessary within every class. By placing such commands into
% a separate file it will be possible to share it with other slide
% classes.
%
% \subsection{The class code}
%
% At this point we input the redefinitions that are necessary for
% \SLiTeX.
% \changes{v2.3g}{1994/05/26}{Use \cs{input} instead of \cs{@@input}}
%    \begin{macrocode}
%<*class>
\input{slides.def}
%    \end{macrocode}
%
%
% Now we are ready for setting up the font tables. As usual, we first
% look for a local configuration file |sfonts.cfg|. If there isn't
% one, we fall back to the default one (|sfonts.def|).
% \changes{v2.2i}{1994/03/08}{Corrected first argument of
%    \cs{IfFileExists}: \file{sfonts.def} to \file{sfonts.cfg}.}
% \changes{v2.3g}{1994/05/26}{Use \cs{InputIfFileExists} instead of
%    \cs{IfFileExists} and \cs{input} instead of \cs{@@input}}
%    \begin{macrocode}
\InputIfFileExists{sfonts.cfg}
           {\typeout{**************************************^^J%
                     *^^J%
                     * Local config file sfonts.cfg used^^J%
                     *^^J%
                     **************************************}}%
           {\input{sfonts.def}}
%    \end{macrocode}
%
% \section{Declaration of Options}
%
% We declare a few options as illegal.
%
%
% \subsection{Setting Paper Sizes}
%
%    The variables |\paperwidth| and |\paperheight| should reflect the
%    physical paper size after trimming. For desk printer output this
%    is usually the real paper size since there is no post-processing.
%    Classes for real book production will probably add other paper
%    sizes and additionally the production of crop marks for trimming.
% \changes{v2.1d}{1993/12/14}{Corrected typo, A4 is not 279 mm high}
%    \begin{macrocode}
\DeclareOption{a4paper}
   {\setlength\paperheight {297mm}%
    \setlength\paperwidth  {210mm}}
\DeclareOption{a5paper}
   {\setlength\paperheight {210mm}%
    \setlength\paperwidth  {148mm}}
\DeclareOption{b5paper}
   {\setlength\paperheight {250mm}%
    \setlength\paperwidth  {176mm}}
\DeclareOption{letterpaper}
   {\setlength\paperheight {11in}%
    \setlength\paperwidth  {8.5in}}
\DeclareOption{legalpaper}
   {\setlength\paperheight {14in}%
    \setlength\paperwidth  {8.5in}}
\DeclareOption{executivepaper}
   {\setlength\paperheight {10.5in}%
    \setlength\paperwidth  {7.25in}}
%    \end{macrocode}
%
%    The option \Lopt{landscape} switches the values of |\paperheight|
%    and |\paperwidth|, assuming the dimensions were given for portrait
%    paper.
%    \begin{macrocode}
\DeclareOption{landscape}
   {\setlength\@tempdima   {\paperheight}%
    \setlength\paperheight {\paperwidth}%
    \setlength\paperwidth  {\@tempdima}}
%    \end{macrocode}
%
%  \subsection{The clock option}

% The option \Lopt{clock} prints the time at the bottom of each note.
% We also define here the commands and counters used to keep track of
% time.
%    \begin{macrocode}
\newif\if@clock \@clockfalse
\DeclareOption{clock}{\@clocktrue
  \AtEndDocument{\typeout{\@arabic\c@minutes\space minutes}}
}%
\newcounter{minutes}%
\newcounter{seconds}%
\newcommand*{\settime}[1]{\setcounter{seconds}{0}\addtime{#1}}%
\newcommand*{\addtime}[1]{\addtocounter{seconds}{#1}%
  \setcounter{minutes}{\value{seconds}}%
  \global \divide \value{minutes} by 60\relax}

%    \end{macrocode}
%
%  \subsection{Two-side or one-side printing}
%
% Two-sided printing is not allowed, so don't declare an option.
% But it is necessary to initialize the switch.
% \changes{v2.2h}{1994/03/07}{Removed declared option twoside.}
%    \begin{macrocode}
\@twosidefalse
%    \end{macrocode}
%
%
%  \subsection{Draft option}
%
%    If the user requests \Lopt{draft} we show any overfull boxes.
%    We could probably add some more interesting stuff to this option.
%    \begin{macrocode}
\DeclareOption{draft}{\setlength\overfullrule{5pt}}
\DeclareOption{final}{\setlength\overfullrule{0pt}}
%    \end{macrocode}
%
%  \subsection{Titlepage option}
%    The default is for a |\maketitle| command to make a new page.
%    \begin{macrocode}
\newif\if@titlepage
\@titlepagetrue
\DeclareOption{titlepage}{\@titlepagetrue}
\DeclareOption{notitlepage}{\@titlepagefalse}
%    \end{macrocode}
%
%  \subsection{Twocolumn printing}
%
%    Two-column printing is again forbidden.
% \changes{v2.3e}{1994/05/22}{twocolumn produces only a warning}
%    \begin{macrocode}
\DeclareOption{onecolumn}{}
\DeclareOption{twocolumn}{%
    \ClassWarning{slides}{No 'twocolumn' layout for slides}}
%    \end{macrocode}
%
%  \subsection{Equation numbering on the left}
%
%    The option \Lopt{leqno} can be used to get the equation numbers
%    on the left side of the equation.
% \changes{v2.2g}{1994/03/01}{Option leqno loads \file{leqno.clo}
%    file.}
%    \begin{macrocode}
\DeclareOption{leqno}{\input{leqno.clo}}
%    \end{macrocode}
%
%  \subsection{Flush left displays}
%
%    The option \Lopt{fleqn} redefines the displayed math environments
%    in such a way that they come out flush left, with an indentation
%    of |\mathindent| from the prevailing left margin.
% \changes{v2.2g}{1994/03/01}{Added fleqn option.}
%    \begin{macrocode}
\DeclareOption{fleqn}{\input{fleqn.clo}}
%    \end{macrocode}
%
%
% \section{Executing Options}
%
%    Here we execute the default options to initialize certain
%    variables.
%    \begin{macrocode}
\ExecuteOptions{letterpaper,final}
%    \end{macrocode}
%
%    The |\ProcessOptions| command causes the execution of the code
%    for every option \Lopt{FOO}
%    which is declared and for which the user typed
%    the \Lopt{FOO} option in his
%    |\documentclass| command.  For every option \Lopt{BAR} he typed,
%    which is not declared, the option is assumed to be a global option.
%    All options will be passed as document options to any
%    |\usepackage| command in the document preamble.
%    \begin{macrocode}
\ProcessOptions
%    \end{macrocode}
%
%  \section{Loading Packages}
%
%  The standard class files do not load additional packages.
%
%
% \section{Document Layout}
%
%
%  In this section we are finally dealing with the nasty typographical
%  details.
%
%
%
% \subsection{Fonts}
%
%    \begin{macrocode}
% FMi:
\def\rmdefault{lcmss}        % no roman
\def\sfdefault{lcmss}
\def\ttdefault{lcmtt}
\def\itdefault{sl}
\def\sldefault{sl}
\def\bfdefault{bx}
%    \end{macrocode}
%    As |\fontshape| gets redefined we need to make sure that the default
%    for |\upshape| is no longer \texttt{up} but again \texttt{n}.
% \changes{v2.4b}{2019/11/04}{Explicitly set \cs{updefault}}
%    \begin{macrocode}
\def\updefault{n}
%    \end{macrocode}
%
%
%  Since the number of parameters to set are very large it seems
%    reasonable to set up one command |\@setfontsize@parms| which will
%    do the work for us.
%
%    \LaTeX\ offers the user commands to change the size of the font,
%    relative to the `main' size. Each relative size changing command
%    |\size| executes the command
%    |\@setfontsize||\size|\meta{font-size}\meta{baselineskip} where:
%
%    \begin{description}
%    \item[\meta{font-size}] The absolute size of the font to use from
%        now on.
%
%    \item[\meta{baselineskip}] The normal value of |\baselineskip|
%        for the size of the font selected. (The actual value will be
%        |\baselinestretch| * \meta{baselineskip}.)
%    \end{description}
%
%    A number of commands, defined in the \LaTeX{} kernel, shorten the
%    following  definitions and are used throughout. They are:
% \begin{center}
% \begin{tabular}{ll@{\qquad}ll@{\qquad}ll}
%  \verb=\@vpt= & 5 & \verb=\@vipt= & 6 & \verb=\@viipt= & 7 \\
%  \verb=\@viiipt= & 8 & \verb=\@ixpt= & 9 & \verb=\@xpt= & 10 \\
%  \verb=\@xipt= & 10.95 & \verb=\@xiipt= & 12 & \verb=\@xivpt= & 14.4\\
%  ...
%  \end{tabular}
%  \end{center}
%
% \begin{macro}{\ifourteenpt}
% \begin{macro}{\iseventeenpt}
% \begin{macro}{\itwentypt}
% \begin{macro}{\itwentyfourpt}
% \begin{macro}{\itwentyninept}
% \begin{macro}{\ithirtyfourpt}
% \begin{macro}{\ifortyonept}
%    For \SLiTeX{}, however, these are not sufficient, and we therefore
%    need to add a few extra, larger, sizes.
%    \begin{macrocode}
\def\ifourteenpt{13.82}
\def\iseventeenpt{16.59}
\def\itwentypt{19.907}
\def\itwentyfourpt{23.89}
\def\itwentyninept{28.66}
\def\ithirtyfourpt{34.4}
\def\ifortyonept{41.28}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@setfontsize@parms}
%    This routine is used in \SliTeX{} to interface font size setting
%    it is modeled after the settings I found in \texttt{slides.sty}, so
%    it probably needs an update. But any class is free to redefine
%    it, as it is used only as an abbreviation.
%    It's syntax is:
% \begin{quote}
%     |\@setfontsize@parms| \\
%     |   |\meta{lineskip} \\
%     |   |\meta{parskip} \\
%     |   |\meta{abovedisplayskip}  \\
%     |   |\meta{belowdisplayskip}  \\
%     |   |\meta{abovedisplayshortskip} \\
%     |   |\meta{belowdisplayshortskip} \\
%     |   |\meta{strut ht} \meta{strut dp}   (without pt)
% \end{quote}
%
% For NFSS1 a similar style existed which did run both with a
% \SliTeX{} with old font selection or with NFSS1. But when no
% separate format is made this doesn't make much sense.
% So the following note is history and would only be true if all NFSS
% stuff would be removed from the file and placed into the format.
% \begin{quote}\small
% Note: To interface the old \texttt{sfonts.tex} the \meta{size} must be
%    hidden in commands denoting the size by its name prefixed with
%    `i', i.e.\ 20pt size is called |\itwentypt| at this point. The
%    NFSS interface will define those sizes to expand to the internal
%    size, e.g.\ 20 but for the old sfonts the command name, e.g.
%    |\itwentypt|, will be used to construct the name |\twentypt| etc.
%
%    This is a crude interface to the old \texttt{sfonts.tex}. It will
%    be a bit slower than the old one because it must define |\@tiny|
%    etc.\ every time a size changes.
% \end{quote}
%
% If classes are set up that are only for use with NFSS then the second
% argument may be an ordinary font size!
% \changes{v2.0d}{1993/11/12}{Replaced all pt by \cs{p@}, corrected
%    definition for \cs{tiny}.}
%
%    \begin{macrocode}
\def\@setfontsize@parms#1#2#3#4#5#6#7#8{%
   \lineskip #1\relax%
   \parskip #2\relax
   \abovedisplayskip #3\relax
   \belowdisplayskip #4\relax
   \abovedisplayshortskip #5\relax
   \belowdisplayshortskip #6\relax
%
%    \end{macrocode}
%    I don't see a reason why the |\strutbox| has a dim different from
%    |\baselineskip| but we will leave it for the moment
%    \begin{macrocode}
  \setbox\strutbox=\hbox{\vrule \@height#7\p@\@depth#8\p@\@width\z@}%
  \baselineskip\baselinestretch\baselineskip
  \normalbaselineskip\baselineskip}
%    \end{macrocode}
%  \end{macro}
%
%    Setting size relations for math scripts:
% \changes{v2.2e}{1994/02/07}{Corrected entry for size 23.89.}
%    \begin{macrocode}
\DeclareMathSizes{13.82}{13.82}{10}{7}
\DeclareMathSizes{16.59}{16.59}{12}{7}
\DeclareMathSizes{19.907}{19.907}{16.59}{13.82}
\DeclareMathSizes{23.89}{23.89}{19.907}{16.59}
\DeclareMathSizes{28.66}{28.66}{23.89}{19.907}
\DeclareMathSizes{34.4}{34.4}{28.66}{23.89}
\DeclareMathSizes{41.28}{41.28}{34.4}{28.66}
%    \end{macrocode}
%
% \begin{macro}{\normalsize}
%    \begin{macrocode}
\def\normalsize{%
      \@setfontsize\normalsize\itwentypt{28\p@ plus3\p@ minus4\p@}%
%            {20}{30\p@ plus3\p@ minus3\p@}%  made a bit shorter
      \@setfontsize@parms
            {2pt}%
            {30\p@ plus18\p@ minus9\p@}%
            {15\p@ plus3\p@ minus3\p@}%
            {10\p@ plus3\p@ minus3\p@}%
            {10\p@ plus3\p@}
            \abovedisplayshortskip
            {17}{7}}
%    \end{macrocode}
% \end{macro}
%
%
%    We initially choose the normalsize font.
%    \begin{macrocode}
\normalsize
%    \end{macrocode}
%
% \begin{macro}{\small}
%    \begin{macrocode}
\def\small{\@setfontsize\small\iseventeenpt{19\p@ plus3\p@ minus\p@}%
           \@setfontsize@parms
            {2\p@}%
            {15\p@ plus15\p@ minus7\p@}%
            {12\p@ plus3\p@ minus3\p@}%
            {9\p@ plus3\p@ minus3\p@}%
            {6\p@ plus3\p@}%
            \abovedisplayshortskip
            {13.5}{5.6}}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\footnotesize}
% \begin{macro}{\scriptsize}
%    \begin{macrocode}
\let\footnotesize=\small
\let\scriptsize=\small
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\tiny}
%    \begin{macrocode}
\def\tiny{\@setfontsize\tiny\ifourteenpt{16\p@ plus2\p@ minus\p@}%
          \@setfontsize@parms
            {2pt}%
            {14\p@ plus3\p@ minus10\p@}%
            {11\p@ plus3\p@ minus10\p@}%
            \abovedisplayskip
            {8\p@ plus3\p@ minus5\p@}%
            {\z@ plus3\p@}%
            {10}{4}}
%    \end{macrocode}
% \end{macro}
%
% Actually copying the code above would be better because this would
% correct the error message. Maybe one should remove the first
% argument of |\set@font@size@parms|.
%
% \begin{macro}{\large}
% \begin{macro}{\Large}
% \begin{macro}{\LARGE}
% \begin{macro}{\huge}
% \begin{macro}{\Huge}
%    \begin{macrocode}
\def\large{\@setfontsize\large\itwentyfourpt{42\p@ plus8\p@ minus5\p@}%
           \@setfontsize@parms
            {2\p@}%
            {40\p@ plus20\p@ minus4\p@}%
            {20\p@ plus8\p@ minus3\p@}%
            \abovedisplayskip
            {10\p@ plus5\p@}%
            \abovedisplayshortskip
            {20}{8.5}}

\def\Large{\@setfontsize\Large\itwentyninept{48\p@ plus10\p@ minus6\p@}%
           \@setfontsize@parms
            {2\p@}%
            {48\p@ plus30\p@ minus6\p@}%
            {24\p@ plus10\p@ minus6\p@}%
            \abovedisplayskip
            {12\p@ plus8\p@}%
            \abovedisplayshortskip
            {27}{11}}

\def\LARGE{\@setfontsize\LARGE\ithirtyfourpt{52\p@ plus10\p@ minus6\p@}%
           \@setfontsize@parms
            {2\p@}%
            {52\p@ plus30\p@ minus6\p@}%
            {24\p@ plus10\p@ minus6\p@}%
            \abovedisplayskip
            {12\p@ plus8\p@}%
            \abovedisplayshortskip
            {27}{11}}

\def\huge{\@setfontsize\huge\ifortyonept{60\p@ plus10\p@ minus6\p@}%
           \@setfontsize@parms
            {2\p@}%
            {60\p@ plus30\p@ minus6\p@}%
            {24\p@ plus10\p@ minus6\p@}%
            \abovedisplayskip
            {12\p@ plus8\p@}%
            \abovedisplayshortskip
            {27}{11}}

\let\Huge\huge
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsection{Paragraphing}
%
% \begin{macro}{\baselinestretch}
%    This is used as a multiplier for |\baselineskip|. The default is
%    to {\em not\/} stretch the baselines.
%    \begin{macrocode}
\renewcommand\baselinestretch{}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\parindent}
%    |\parindent| is the width of the paragraph indentation.
%    \begin{macrocode}
\setlength\parindent{\z@}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@lowpenalty}
% \begin{macro}{\@medpenalty}
% \begin{macro}{\@highpenalty}%
%    The commands |\nopagebreak| and |\nolinebreak| put in penalties
%    to discourage these breaks at the point they are put in.
%    They use |\@lowpenalty|, |\@medpenalty| or |\@highpenalty|,
%    dependent on their argument.
%    \begin{macrocode}
\@lowpenalty   51
\@medpenalty  151
\@highpenalty 301
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\clubpenalty}
% \begin{macro}{\widowpenalty}
%    These penalties are use to discourage club and widow lines.
%    Because we use their default values we only show them here,
%    commented out.
%    \begin{macrocode}
% \clubpenalty  150
% \widowpenalty 150
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\displaywidowpenalty}
% \begin{macro}{\predisplaypenalty}
% \begin{macro}{\postdisplaypenalty}
%    Discourage (but not so much) widows in front of a math display
%    and forbid breaking directly in front of a display. Allow break
%    after a display without a penalty. Again the default values are
%    used, therefore we only show them here.
%    \begin{macrocode}
% \displaywidowpenalty 50
% \predisplaypenalty   10000
% \postdisplaypenalty  0
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\interlinepenalty}
%    Allow the breaking of a page in the middle of a paragraph.
%    \begin{macrocode}
% \interlinepenalty 0
%    \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\brokenpenalty}
%    We allow the breaking of a page after a hyphenated line.
%    \begin{macrocode}
% \brokenpenalty 0
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Page Layout}
%
%    All margin dimensions are measured from a point one inch from the
%    top and lefthand side of the page.
%
% \subsubsection{Vertical spacing}
%
% \begin{macro}{\headheight}
% \begin{macro}{\headsep}
% \begin{macro}{\topskip}
%    The |\headheight| is the height of the box that will contain the
%    running head. The |\headsep| is the distance between the bottom
%    of the running head and the top of the text. |\topskip| is the
%    |\baselineskip| for the first line on a page.
%    \begin{macrocode}
\setlength\headheight{14\p@}
\setlength\headsep   {15\p@}
\setlength\topskip   {30\p@}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\footskip}
%    The distance from the baseline of the box which contains the
%    running footer to the baseline of last line of text is controlled
%    by the |\footskip|.
%    Bottom of page:
%    \begin{macrocode}
\setlength\footskip{25\p@}   %
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\maxdepth}
% \begin{macro}{\@maxdepth}
% \changes{v2.3c}{1994/05/06}{Added setting of \cs{maxdepth} and
%    \cs{@maxdepth}}
%    The \TeX\ primitive register |\maxdepth| has a function that is
%    similar to that of |\topskip|. The register |\@maxdepth| should
%    always contain a copy of |\maxdepth|. In both plain \TeX\ and
%    \LaTeX~2.09 |\maxdepth| had a fixed value of \texttt{4pt}; in
%    native \LaTeX2e\ mode we let the value depend on the typesize. We
%    set it so that |\maxdepth| $+$ |\topskip| $=$ typesize $\times
%    1.5$. As it happens, in these classes |\topskip| is equal to the
%    typesize, therefor we set |\maxdepth| to half the value of
%    |\topskip|.
%    \begin{macrocode}
\if@compatibility
  \setlength\maxdepth{4\p@}
\else
  \setlength\maxdepth{.5\topskip}
\fi
\setlength\@maxdepth\maxdepth
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \subsubsection{The dimension of text}
%
% \begin{macro}{\textwidth}
%    When we are in compatibility mode we have to make sure that the
%    dimensions of the printed area are not different from what the
%    user was used to see.
%
%    \begin{macrocode}
\if@compatibility
  \setlength\textwidth{460\p@}
%    \end{macrocode}
%    When we are not in compatibility mode we can set some of the
%    dimensions differently, taking into account the paper size for
%    instance.
%    \begin{macrocode}
\else
%    \end{macrocode}
%    First, we calculate the maximum textwidth, which depends on the
%    papersize. Then we calculate the approximate length of 65
%    characters, which should be the maximum length of a line of text.
%    The calculated values are stored in |\@tempdima| and |\@tempdimb|.
%    \begin{macrocode}
  \setlength\@tempdima{\paperwidth}
  \addtolength\@tempdima{-2in}
  \setbox\@tempboxa\hbox{\rmfamily im}
  \setlength\@tempdimb{.5\wd\@tempboxa}
  \setlength\@tempdimb{65\@tempdimb}
%    \end{macrocode}
%
%    Now we can set the |\textwidth|, depending on whether we will be
%    setting one or two columns.
%
%    The text should not be wider than the minimum
%    of the paperwidth (minus 2 inches for the margins) and the
%    maximum length of a line as defined by the number of characters.
%    \begin{macrocode}
  \ifdim\@tempdima>\@tempdimb\relax
    \setlength\textwidth{\@tempdimb}
  \else
    \setlength\textwidth{\@tempdima}
  \fi
\fi
%    \end{macrocode}
%
%    Here we modify the width of the text a little to be a whole
%    number of points.
%    \begin{macrocode}
\@settopoint\textwidth
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\columnwidth}
% \begin{macro}{\columnsep}
% \begin{macro}{\columnseprule}
%    \begin{macrocode}
\columnwidth \textwidth
\columnsep 10pt
\columnseprule \z@
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \begin{macro}{\textheight}
%    Now that we have computed the width of the text, we have to take
%    care of the height. The |\textheight| is the height of text
%    (including footnotes and figures, excluding running head and
%    foot).
%
%    First make sure that the compatibility mode gets the same
%    dimensions as we had with \LaTeX2.09. The number of lines was
%    calculated as the floor of the old |\textheight| minus
%    |\topskip|, divided by |\baselineskip| for |\normalsize|. The
%    old value of |\textheight| was 528pt.
%
%    \begin{macrocode}
\if@compatibility
  \setlength\textheight{600\p@}
%    \end{macrocode}
%
%    Again we compute this, depending on the papersize and depending
%    on the baselineskip that is used, in order to have a whole number
%    of lines on the page.
%    \begin{macrocode}
\else
  \setlength\@tempdima{\paperheight}
%    \end{macrocode}
%
%    We leave at least a 1 inch margin on the top and the bottom of
%    the page.
%    \begin{macrocode}
  \addtolength\@tempdima{-2in}
%    \end{macrocode}
%
%    We also have to leave room for the running headers and footers.
%    \begin{macrocode}
  \addtolength\@tempdima{-1in}
%    \end{macrocode}
%
%    Then we divide the result by the current |\baselineskip| and
%    store this in the count register |\@tempcnta|, which then
%    contains the number of lines that fit on this page.
%    \begin{macrocode}
  \divide\@tempdima\baselineskip
  \@tempcnta=\@tempdima
%    \end{macrocode}
%
%    From this we can calculate the height of the text.
%    \begin{macrocode}
  \setlength\textheight{\@tempcnta\baselineskip}
\fi
%    \end{macrocode}
%
%    The first line on the page has a height of |\topskip|.
%    \begin{macrocode}
\advance\textheight by \topskip
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Margins}
%
% \begin{macro}{\oddsidemargin}
% \begin{macro}{\evensidemargin}
% \begin{macro}{\marginparwidth}
%    First we give the values for the compatibility mode.
%
%    Values for two-sided printing:
%    \begin{macrocode}
\if@compatibility
   \setlength\oddsidemargin  {17\p@}
   \setlength\evensidemargin {17\p@}
   \setlength\marginparwidth {20\p@}
\else
%    \end{macrocode}
%
%    When we are not in compatibility mode we can take the dimensions
%    of the selected paper into account.
%
%    We center the text on the page, by
%    calculating the difference between |textwidth| and
%    |\paperwidth|$-$|2in|. Half of that difference is then used for
%    the margin. The amount of space that can be used for marginal
%    notes is at least 0.8~inch, to which we add any `leftover' space.
%    \begin{macrocode}
  \setlength\@tempdima        {\paperwidth}
  \addtolength\@tempdima      {-2in}
  \addtolength\@tempdima      {-\textwidth}
  \setlength\oddsidemargin    {.5\@tempdima}
  \setlength\marginparwidth   {.8in}
  \addtolength\marginparwidth {.5\@tempdima}
%    \end{macrocode}
%
%    The |\evensidemargin| can now be computed from the values set
%    above.
%    \begin{macrocode}
\setlength\evensidemargin  {\paperwidth}
\addtolength\evensidemargin{-2in}
\addtolength\evensidemargin{-\textwidth}
\addtolength\evensidemargin{-\oddsidemargin}
\fi
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\marginparsep}
% \begin{macro}{\marginparpush}
%    The horizontal space between the main text and marginal notes is
%    determined by |\marginparsep|, the minimum vertical separation
%    between two marginal notes is controlled by |\marginparpush|.
%    \begin{macrocode}
\setlength\marginparsep {5\p@}
\setlength\marginparpush{5\p@}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\topmargin}
%    The |\topmargin| is the distance between the top of `the
%    printable area' --which is 1 inch below the top of the paper--
%    and the top of the box which contains the running head.
%
%    It can now be computed from the values set above.
%    \begin{macrocode}
\if@compatibility
  \setlength\topmargin{-10pt}
\else
  \setlength\topmargin{\paperheight}
  \addtolength\topmargin{-2in}
  \addtolength\topmargin{-\headheight}
  \addtolength\topmargin{-\headsep}
  \addtolength\topmargin{-\textheight}
  \addtolength\topmargin{-\footskip}     % this might be wrong!
%    \end{macrocode}
%    By changing the factor in the next line the complete page
%    can be shifted vertically.
%    \begin{macrocode}
  \addtolength\topmargin{-.5\topmargin}
\fi
\@settopoint\topmargin
%    \end{macrocode}
% \end{macro}
%
%
% \subsubsection{Footnotes}
%
% \begin{macro}{\footnotesep}
%    |\footnotesep| is the height of the strut placed at the beginning
%    of every footnote. It equals the  height of a normal
%    |\footnotesize| strut in this
%    class, thus no extra space occurs between footnotes.
%    \begin{macrocode}
\setlength\footnotesep{20\p@}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\footins}
%    |\skip\footins| is the space between the last line of the main
%    text and the top of the first footnote.
%    \begin{macrocode}
\setlength{\skip\footins}{10\p@ \@plus 2\p@ \@minus 4\p@}
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Page Styles}
%
%    The page style \pstyle{foo} is defined by defining the command
%    |\ps@foo|.   This command should make only local definitions.
%    There should be no stray spaces in the definition, since they
%    could lead to mysterious extra spaces in the output (well, that's
%    something that should be always avoided).
%
% \begin{macro}{\@evenhead}
% \begin{macro}{\@oddhead}
% \begin{macro}{\@evenfoot}
% \begin{macro}{\@oddfoot}
%    The |\ps@...| command defines the macros |\@oddhead|,
%    |\@oddfoot|, |\@evenhead|, and |\@evenfoot| to define the running
%    heads and feet---e.g., |\@oddhead| is the macro to produce the
%    contents of the heading box for odd-numbered pages.  It is called
%    inside an |\hbox| of width |\textwidth|.
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%
%  The page styles of slides is determined by the 'slide' page style,
% the slide environment executing a |\thispagestyle{slide}| command.
% The page styles of overlays and notes are similarly determined by
% 'overlay' and 'note' page styles.  The command standard 'headings',
% 'plain' and 'empty' page styles work by redefining the 'slide',
% 'overlay', and 'note' styles.
%
% \changes{v2.3q}{1995/09/20}{Wrap some long lines, and use \cs{null}.}
% \begin{macro}{\ps@headings}
%    \begin{macrocode}
\if@compatibility
\def\ps@headings{%
\def\ps@slide{\def\@oddfoot{\@mainsize +\hfil\hb@xt@3em{\theslide
                                                          \hss}}%
 \def\@oddhead{\@mainsize +\hfil +}%
 \def\@evenfoot{\@mainsize +\hfil\hb@xt@3em{\theslide\hss}}%
 \def\@evenhead{\@mainsize +\hfil +}}

\def\ps@overlay{\def\@oddfoot{\@mainsize +\hfil\hb@xt@3em{\theoverlay
                                                           \hss}}%
 \def\@oddhead{\@mainsize +\hfil +}%
 \def\@evenfoot{\@mainsize +\hfil\hb@xt@3em{\theoverlay\hss}}%
 \def\@evenhead{\@mainsize +\hfil +}}
\def\ps@note{\def\@oddfoot{\@mainsize \hbox{}\hfil\thenote}%
 \def\@oddhead{}%
 \def\@evenfoot{\@mainsize \hbox{}\hfil\thenote}%
 \def\@evenhead{}}}
%
\else %%if@compatibility
%
\def\ps@headings{%
  \def\ps@slide{%
    \def\@oddfoot{\@mainsize \mbox{}\hfil\hb@xt@3em{\theslide\hss}}%
    \def\@oddhead{}%
    \def\@evenfoot{\@mainsize \mbox{}\hfil\hb@xt@3em{\theslide\hss}}%
    \def\@evenhead{}}

  \def\ps@overlay{%
    \def\@oddfoot{\@mainsize \mbox{}\hfil\hb@xt@3em{\theoverlay\hss}}%
    \def\@oddhead{}%
    \def\@evenfoot{\@mainsize \mbox{}\hfil\hb@xt@3em{\theoverlay\hss}}%
    \def\@evenhead{}}

  \def\ps@note{%
    \def\@oddfoot{%
      \@mainsize
      \if@clock
        \fbox{\large \@arabic\c@minutes\space min}%
      \else
        \null
      \fi
      \hfil\thenote}%
    \def\@oddhead{}%
    \def\@evenfoot{%
      \@mainsize
      \if@clock
        \fbox{\large \@arabic\c@minutes\space min}%
      \else
        \null
      \fi
      \hfil\thenote}%
    \def\@evenhead{}}}
\fi  %% if@compatibility
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\ps@plain}
%    \begin{macrocode}
\def\ps@plain{\def\ps@slide{%
 \def\@oddfoot{\@mainsize \mbox{}\hfil\hb@xt@3em{\theslide\hss}}%
 \def\@oddhead{}%
 \def\@evenfoot{\@mainsize \mbox{}\hfil\hb@xt@3em{\theslide\hss}}%
 \def\@evenhead{}}
\def\ps@overlay{\def\@oddfoot{\@mainsize
   \mbox{}\hfil\hb@xt@3em{\theoverlay\hss}}%
 \def\@oddhead{}%
 \def\@evenfoot{\@mainsize \mbox{}\hfil\hb@xt@3em{\theoverlay\hss}}%
 \def\@evenhead{}}
\def\ps@note{\def\@oddfoot{\@mainsize \hbox{}\hfil\thenote}%
 \def\@oddhead{}%
 \def\@evenfoot{\@mainsize \hbox{}\hfil\thenote}%
 \def\@evenhead{}}}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\ps@empty}
%    \begin{macrocode}
\def\ps@empty{%
\def\ps@slide{\def\@oddhead{}\def\@oddfoot{}%
\def\@evenhead{}\def\@evenfoot{}}%
\def\ps@overlay{\def\@oddhead{}\def\@oddfoot{}%
\def\@evenhead{}\def\@evenfoot{}}%
\def\ps@note{\def\@oddhead{}\def\@oddfoot{}%
\def\@evenhead{}\def\@evenfoot{}}}
%    \end{macrocode}
% \end{macro}
%
% Default definition the 'slide', 'overlay', and 'note' page styles.
%    \begin{macrocode}
\ps@headings
%    \end{macrocode}
% Set ordinary page style to 'empty'
%    \begin{macrocode}
\let\@oddhead\@empty\let\@oddfoot\@empty
\let\@evenhead\@empty\let\@evenfoot\@empty
%    \end{macrocode}
%
%
% \subsection{Providing math {\em versions}}
%
%  \LaTeX{} provides two {\em versions\/}. We call them
%  \textsf{normal} and \textsf{bold}, respectively.
%  \SliTeX{} does not have a \textsf{bold} version. But we treat the
%  invisible characters as a version. The only thing we have to take
%  care of is to ensure that we have exactly the same fonts in both
%  versions available.
%
%    \begin{macrocode}
\DeclareMathVersion{invisible}
%    \end{macrocode}
%
% Now we define the basic {\em math groups\/} used by \LaTeX{}.  Later
% on, in packages some other {\em math groups}, e.g., the AMS
% symbol fonts, will be defined.
%
%  As a default I used serif fonts for mathgroup 0 to get things like
% \verb+\log+ look right.
%    \begin{macrocode}
\SetSymbolFont{operators}{normal}
                 {OT1}{lcmss}{m}{n}

\SetSymbolFont{letters}{normal}
                 {OML}{lcmm}{m}{it}
\SetSymbolFont{symbols}{normal}
                 {OMS}{lcmsy}{m}{n}
\SetSymbolFont{largesymbols}{normal}
                 {OMX}{lcmex}{m}{n}

\SetSymbolFont{operators}{invisible}
                 {OT1}{lcmss}{m}{In}
\SetSymbolFont{letters}{invisible}
                 {OML}{lcmm}{m}{Iit}
\SetSymbolFont{symbols}{invisible}
                 {OMS}{lcmsy}{m}{In}
\SetSymbolFont{largesymbols}{invisible}
                  {OMX}{lcmex}{m}{In}


\def\@mainsize{\visible\tiny}
%    \end{macrocode}
%
%
%  \subsection{Environments}
%
% \begin{environment}{titlepage}
%    This environment starts a new page, with pagestyle \pstyle{empty}
%    and sets the page counter to 0.
%    \begin{macrocode}
\newenvironment{titlepage}
     {\newpage
      \thispagestyle{empty}%
      \setcounter{page}{\z@}}
     {\newpage}
%    \end{macrocode}
% \end{environment}
%
% \subsubsection{General List Parameters}
%
%    The following commands are used to set the default values for the
%    list environment's parameters. See the \LaTeX{} manual for an
%    explanation of the meaning of the parameters.
%
% \begin{macro}{\leftmargini}
% \begin{macro}{\leftmarginii}
% \begin{macro}{\leftmarginiii}
% \begin{macro}{\leftmarginiv}
% \begin{macro}{\leftmarginv}
% \begin{macro}{\leftmarginvi}
%    \begin{macrocode}
\setlength\leftmargini   {38\p@}
\setlength\leftmarginii  {30\p@}
\setlength\leftmarginiii {20\p@}
\setlength\leftmarginiv  {15\p@}
\setlength\leftmarginv   {15\p@}
\setlength\leftmarginvi  {10\p@}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\@listi}
% \begin{macro}{\@listii}
% \begin{macro}{\@listiii}
% \begin{macro}{\@listiv}
% \begin{macro}{\@listv}
% \begin{macro}{\@listvi}
%    These commands set the values of |\leftmargin|, |\parsep|,
%    |\topsep|, and |\itemsep| for the various levels of lists.
% \changes{v2.3z}{1997/08/15}{Add initialization of \cs{leftmargin} to
%    \cs@listi.}
%    It is even necessary to initialize |\leftmargin| in |\@listi|,
%    i.e. for a level one list, as a list environment may appear
%    inside a \texttt{trivlist}, for example inside a \texttt{theorem}
%    environment.
%    \begin{macrocode}
\def\@listi{\leftmargin\leftmargini
            \parsep .5\parskip
            \topsep \parsep
            \itemsep\parskip
            \partopsep \z@}

\def\@listii{\leftmargin\leftmarginii
             \labelwidth\leftmarginii
             \advance\labelwidth-\labelsep
             \parsep .5\parskip
             \topsep \parsep
             \itemsep\parskip}
\def\@listiii{\leftmargin\leftmarginiii
              \labelwidth\leftmarginiii
              \advance\labelwidth-\labelsep}
\def\@listiv{\leftmargin\leftmarginiv
             \labelwidth\leftmarginiv
             \advance\labelwidth-\labelsep}
\def\@listv{\leftmargin\leftmarginv
            \labelwidth\leftmarginv
            \advance\labelwidth-\labelsep}
\def\@listvi{\leftmargin\leftmarginvi
             \labelwidth\leftmarginvi
             \advance\labelwidth-\labelsep}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
%    Here we initialize |\leftmargin| and |\labelwidth|.
%    \begin{macrocode}
\leftmargin\leftmargini
\labelwidth\leftmargini\advance\labelwidth-\labelsep
%    \end{macrocode}
%
%
%    \subsubsection{Paragraph-formatting environments}
%
% \begin{environment}{verse}
%    Inside a |verse| environment, |\\| ends a line, and
%    line continuations are indented further.
%    A blank line makes new paragraph with |\parskip| space.
%    \begin{macrocode}
\newenvironment{verse}{\let\\=\@centercr
                       \list{}{\itemsep       \z@
                               \itemindent    -15\p@
                               \listparindent \itemindent
                               \rightmargin   \leftmargin
                               \advance\leftmargin 15\p@}%
                       \item[]}
                      {\endlist}
%    \end{macrocode}
% \end{environment}
%
% \begin{environment}{quotation}
%    The |quotation| environment fills lines, indents paragraphs.
%    \begin{macrocode}
\newenvironment{quotation}{\list{}{\listparindent 20\p@
                                   \itemindent\listparindent
                                   \rightmargin\leftmargin}%
                           \item[]}
                          {\endlist}
%    \end{macrocode}
% \end{environment}
%
% \begin{environment}{quote}
%    The |quote| environment is the same as the |quotation| environment,
%    except that there is no paragraph indentation.
%    \begin{macrocode}
\newenvironment{quote}{\list{}{\rightmargin\leftmargin}\item[]}
                      {\endlist}
%    \end{macrocode}
% \end{environment}
%
%
%    \subsubsection{List-making environments}
%
%
% \begin{environment}{description}
%    The description environment is defined here -- while the itemize
%    and enumerate environments are defined in the \LaTeX{} format.
%
%    \begin{macrocode}
\newenvironment{description}{\list{}{\labelwidth\z@
                                     \itemindent-\leftmargin
                                     \let\makelabel\descriptionlabel}}
                            {\endlist}
%    \end{macrocode}
% \end{environment}
%
% \begin{macro}{\descriptionlabel}
%  To change the formatting of the label, you must redefine
%  |\descriptionlabel|.
%    \begin{macrocode}
\newcommand*{\descriptionlabel}[1]{\hspace\labelsep
                                \normalfont\bfseries #1}

%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Enumerate}
%
%    The enumerate environment uses  four counters: \Lcount{enumi},
%    \Lcount{enumii}, \Lcount{enumiii} and \Lcount{enumiv}, where
%    \Lcount{enumN} controls the numbering of the Nth level
%    enumeration.
%
% \begin{macro}{\theenumi}
% \begin{macro}{\theenumii}
% \begin{macro}{\theenumiii}
% \begin{macro}{\theenumiv}
%    The counters are already defined in the \LaTeX{} format, but their
%    representation is changed here.
%
%    \begin{macrocode}
\renewcommand\theenumi{\@arabic\c@enumi}
\renewcommand\theenumii{\@alph\c@enumii}
\renewcommand\theenumiii{\@roman\c@enumiii}
\renewcommand\theenumiv{\@Alph\c@enumiv}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\labelenumi}
% \begin{macro}{\labelenumii}
% \begin{macro}{\labelenumiii}
% \begin{macro}{\labelenumiv}
%    The label for each item is generated by the four commands
%    |\labelenumi| \ldots\ |\labelenumiv|.
% \changes{v2.3k}{1994/12/12}{Handle the \cs{label...} commands as in
%    the other class files}
%    \begin{macrocode}
\newcommand\labelenumi{\theenumi.}
\newcommand\labelenumii{(\theenumii)}
\newcommand\labelenumiii{\theenumiii.}
\newcommand\labelenumiv{\theenumiv.}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\p@enumii}
% \begin{macro}{\p@enumiii}
% \begin{macro}{\p@enumiv}
%    The expansion of |\p@enumN||\theenumN| defines the output of a
%    |\ref| command when referencing an item of the Nth level of an
%    enumerated list.
%    \begin{macrocode}
\renewcommand\p@enumii{\theenumi}
\renewcommand\p@enumiii{\theenumi(\theenumii)}
\renewcommand\p@enumiv{\p@enumiii\theenumiii}
%    \end{macrocode}
% \end{macro}
% \end{macro}
% \end{macro}
%
% \subsubsection{Itemize}
%
%
% \begin{macro}{\labelitemi}
% \begin{macro}{\labelitemii}
% \changes{v2.3x}{1996/08/25}{replaced -{}- with \cs{textendash}}
% \begin{macro}{\labelitemiii}
% \begin{macro}{\labelitemiv}
%    Itemization is controlled by four commands: |\labelitemi|,
%    |\labelitemii|, |\labelitemiii|, and |\labelitemiv|, which\
%    define the labels of the various itemization levels.
%    \begin{macrocode}
\newcommand\labelitemi{$\m@th\bullet$}
\newcommand\labelitemii{\normalfont\bfseries \textendash}
\newcommand\labelitemiii{$\m@th\ast$}
\newcommand\labelitemiv{$\m@th\cdot$}
%    \end{macrocode}
%    \end{macro}
%    \end{macro}
%    \end{macro}
%    \end{macro}
%
% \subsection{Setting parameters for existing environments}
%
% \subsubsection{Array and tabular}
%
% \begin{macro}{\arraycolsep}
%    The columns in an array environment are separated by
%    2|\arraycolsep|.% Array and tabular environment parameters
%    \begin{macrocode}
\setlength\arraycolsep{8\p@}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\tabcolsep}
%    The columns in an tabular environment are separated by
%    2|\tabcolsep|.
%    \begin{macrocode}
\setlength\tabcolsep{10\p@}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\arrayrulewidth}
%    The width of rules in the array and tabular environments is given
%    by  the length parameter|\arrayrulewidth|.
%    \begin{macrocode}
\setlength\arrayrulewidth{.6\p@}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\doublerulesep}
%    The space between adjacent rules in the array and tabular
%    environments is given by |\doublerulesep|.
%    \begin{macrocode}
\setlength\doublerulesep{3\p@}
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Tabbing}
%
% \begin{macro}{\tabbingsep}
%    This controls the space that the |\'| command puts in. (See
%    \LaTeX{} manual for an explanation.)
%    \begin{macrocode}
\labelsep 10pt
\setlength\tabbingsep{\labelsep}
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Minipage}
%
% \begin{macro}{\@minipagerestore}
%    The macro |\@minipagerestore| is called upon entry to a minipage
%    environment to set up things that are to be handled differently
%    inside a minipage environment. In the current styles, it does
%    nothing.
% \end{macro}
%
% \begin{macro}{\@mpfootins}
%    Minipages have their own footnotes; |\skip||\@mpfootins| plays
%    same r\^ole for footnotes in a minipage as |\skip||\footins| does
%    for ordinary footnotes.
%
%    \begin{macrocode}
\skip\@mpfootins = \skip\footins
%    \end{macrocode}
% \end{macro}
%
% \subsubsection{Framed boxes}
%
% \begin{macro}{\fboxsep}
%    The space left by |\fbox| and |\framebox| between the box and the
%    text in it.
% \begin{macro}{\fboxrule}
%    The width of the rules in the box made by |\fbox| and |\framebox|.
%    \begin{macrocode}
\setlength\fboxsep{5\p@}
\setlength\fboxrule{.6\p@}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
% \begin{macro}{\theequation}
%    The equation number will be typeset as arabic numerals.
%    \begin{macrocode}
\def\theequation{\@arabic\c@equation}
%    \end{macrocode}
% \end{macro}
%
%
% \begin{macro}{\jot}
%    |\jot| is the extra space added between lines of an eqnarray
%    environment. The default value is used.
%    \begin{macrocode}
% \setlength\jot{3pt}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@eqnnum}
%    The macro |\@eqnnum| defines how equation numbers are to appear in
%    equations. Again the default is used.
%
%    \begin{macrocode}
% \def\@eqnnum{(\theequation)}
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{Font changing}
%
% \changes{v2.3j}{1994/11/10}{fixed a few typos}
%
%    Here we supply the declarative font changing commands that were
%    common in \LaTeX\ version 2.09 and earlier. These commands work
%    in text mode \emph{and} in math mode. They are provided for
%    compatibility, but one should start using the |\text...| and
%    |\math...| commands instead. These commands are redefined using
%    |\DeclareOldFontCommand|, a command with three arguments: the
%    user command to be defined, \LaTeX\ commands to execute in text
%    mode and \LaTeX\ commands to execute in math mode.
%
%  \begin{macro}{\rm}
%  \begin{macro}{\tt}
%  \begin{macro}{\sf}
% \changes{v2.2}{1993/12/18}{Changed \cs{@newfontswitch} to
%    \cs{@renewfontswitch}.}
% \changes{v2.3a}{1994/04/14}{\cs{@renewfontswitch} has become
%    \cs{DeclareOldFontCommand}}
%
%    The commands to change the family. When in compatibility mode we
%    select the `default' font first, to get \LaTeX2.09 behaviour.
%    \begin{macrocode}
\DeclareOldFontCommand{\rm}{\normalfont\rmfamily}{\mathrm}
\DeclareOldFontCommand{\sf}{\normalfont\sffamily}{\mathsf}
\DeclareOldFontCommand{\tt}{\normalfont\ttfamily}{\mathtt}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
%  \begin{macro}{\bf}
%    The command to change to the bold series. One should use
%    |\mdseries| to explicitly switch back to medium series.
% \changes{v2.2}{1993/12/18}{Changed \cs{@newfontswitch} to
%    \cs{@renewfontswitch}.}
%    \begin{macrocode}
\DeclareOldFontCommand{\bf}{\normalfont\bfseries}{\mathbf}
%    \end{macrocode}
%  \end{macro}
%
%  \begin{macro}{\sl}
%  \begin{macro}{\it}
%  \begin{macro}{\sc}
% \changes{v2.2}{1993/12/18}{Changed \cs{@newfontswitch} to
%    \cs{@renewfontswitch}.}
%    And the commands to change the shape of the font. The slanted and
%    small caps shapes are not available by default as math alphabets,
%    so those changes do nothing in math mode. One should use
%    |\upshape| to explicitly change back to the upright shape.
%    \begin{macrocode}
\DeclareOldFontCommand{\it}{\normalfont\itshape}{\mathit}
\DeclareOldFontCommand{\sl}{\normalfont\slshape}{\relax}
\DeclareOldFontCommand{\sc}{\normalfont\scshape}{\relax}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%  \end{macro}
%
% \begin{macro}{\cal}
% \changes{v2.1d}{1993/12/14}{Macro added}
% \begin{macro}{\mit}
% \changes{v2.1d}{1993/12/14}{Macro added}
%
%    The commands |\cal| and |\mit| should only be used in math mode,
%    outside math mode they have no effect. Currently the New Font
%    Selection Scheme defines these commands to generate warning
%    messages. Therefore we have to define them `by hand'.
% \changes{v2.3k}{1994/12/12}{Now define \cs{cal} and \cs{mit} using
%    \cs{DeclareRobustCommand*}}
%    \begin{macrocode}
\DeclareRobustCommand*{\cal}{\@fontswitch{\relax}{\mathcal}}
\DeclareRobustCommand*{\mit}{\@fontswitch{\relax}{\mathnormal}}
%    \end{macrocode}
%  \end{macro}
%  \end{macro}
%
% \subsection{Footnotes}
%
%
% \begin{macro}{\footnoterule}
%    Usually, footnotes are separated from the main body of the text
%    by a small rule. This rule is drawn by the macro |\footnoterule|.
%    We have to make sure that the rule takes no vertical space (see
%    \file{plain.tex}).  The resulting rule will appear on all color
%    layers, so it's best not to draw a rule.
%    \begin{macrocode}
\renewcommand\footnoterule{}
% \let \footnoterule = \relax
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\c@footnote}
% \begin{macro}{\thefootnote}
%    Footnotes are numbered within slides, overlays, and notes and
%    numbered with $\ast$, $\dagger$, etc.
%    \begin{macrocode}
% \newcounter{footnote}
\def\thefootnote{\fnsymbol{footnote}}
\@addtoreset{footnote}{slide}
\@addtoreset{footnote}{overlay}
\@addtoreset{footnote}{note}
%    \end{macrocode}
% \end{macro}
% \end{macro}
%
%
% \begin{macro}{\@makefntext}
% \changes{v2.2i}{1994/03/08}{Always call \cs{@makefnmark}.}
%    The footnote mechanism of \LaTeX{} calls the macro |\@makefntext|
%    to produce the actual footnote. The macro gets the text of the
%    footnote as its argument and should use |\@makefnmark| to produce
%    the mark of the footnote. The macro |\@makefntext| is called when
%    effectively inside a |\parbox| of width |\columnwidth| (i.e.,
%    with |\hsize| = |\columnwidth|).
%
%   An example of what can be achieved is given by the following piece
%   of \TeX\ code.
% \begin{verbatim}
%          \long\def\@makefntext#1{%
%             \@setpar{\@@par
%                      \@tempdima = \hsize
%                      \advance\@tempdima-10pt
%                      \parshape \@ne 10pt \@tempdima}%
%             \par
%             \parindent 1em\noindent
%             \hbox to \z@{\hss\@makefnmark}#1}
% \end{verbatim}
%    The effect of this definition is that all lines of the footnote
%    are indented by 10pt, while the first line of a new paragraph is
%    indented by 1em. To change these dimensions, just substitute the
%    desired value for `10pt' (in both places) or `1em'.  The mark is
%    flushright against the footnote.
%
%    In these document classes we use a simpler macro, in which the
%    footnote text is set like an ordinary text paragraph, with no
%    indentation except on the first line of a paragraph, and the
%    first line of the footnote. Thus, all the macro must do is set
%    |\parindent| to the appropriate value for succeeding paragraphs
%    and put the proper indentation before the mark.
%
%    \begin{macrocode}
\long\def\@makefntext#1{
    \noindent
    \hangindent 10\p@
    \hb@xt@10\p@{\hss\@makefnmark}#1}
%    \end{macrocode}
% \end{macro}
%
% \begin{macro}{\@makefnmark}
%    The footnote markers that are printed in the text to point to the
%    footnotes should be produced by the macro |\@makefnmark|. We use
%    the default definition for it.
%    \begin{macrocode}
%\def\@makefnmark{\hbox{$^{\@thefnmark}\m@th$}}
%    \end{macrocode}
% \end{macro}
%
%
% \subsection{The title}
%     The commands |\title|, |\author|, and |\date| are already
%     defined, so here we just define |\maketitle|.
%
% \changes{v2.3s}{1995/10/10}{Move \cs{par} inside the scope of
%               \cs{Large}, to get even line spacing.}
%    \begin{macrocode}
\newcommand\maketitle{{\centering {\Large \@title \par}%
     \@author \par \@date\par}%
     \if@titlepage \break \fi}
%    \end{macrocode}

% \section{Initialization}
%
% \subsection{Date}
%
% \begin{macro}{\today}
%    This macro uses the \TeX\ primitives |\month|, |\day| and |\year|
%    to provide the date of the \LaTeX-run.
%    \begin{macrocode}
\newcommand\today{\ifcase\month\or
  January\or February\or March\or April\or May\or June\or
  July\or August\or September\or October\or November\or December\fi
  \space\number\day, \number\year}
%    \end{macrocode}
% \end{macro}
%
%
% Default initializations
%
%    \begin{macrocode}
\pagenumbering{arabic}
\onecolumn
%</class>
%    \end{macrocode}
%
% \subsection{Basic code}
%
% The code below is basically a copy of |slitex.tex| with some
% changes.
%
% Global changes so far:
%
% \changes{FMi}{1990/06/01}{\cs{gdef}\cs{@slidesw} ... replaced by a
%    \cs{newifG} which is similar to \cs{newif} but uses \cs{global}
%    inside.}
%
%
% \subsubsection{Hacks for slide macros}
%
%    \begin{macrocode}
%<*cmd>
\message{hacks,}

\outer\def\newifG#1{\count@\escapechar \escapechar\m@ne
  \expandafter\expandafter\expandafter
   \edef\@ifG#1{true}{\global\let\noexpand#1\noexpand\iftrue}%
  \expandafter\expandafter\expandafter
   \edef\@ifG#1{false}{\global\let\noexpand#1\noexpand\iffalse}%
  \@ifG#1{false}\escapechar\count@} % the condition starts out false
\def\@ifG#1#2{\csname\expandafter\ifG@\string#1#2\endcsname}
{\uccode`1=`i \uccode`2=`f \uccode`3=`G \uppercase{\gdef\ifG@123{G}}}
 % `ifG' is required

\def\@gobbletoend#1{\def\@argend{#1}\@ggobtoend}

\long\def\@ggobtoend#1\end#2{\fi\def\reserved@a{#2}%
\ifx\reserved@a\@argend\else\@ggobtoend\fi}
%    \end{macrocode}
% FMi: I don't see any reason for this command since |\fi| is hidden
%      anyway in the replacement text
% |\def\@xfi{\fi}|
%    \begin{macrocode}
 \message{slides,}
%    \end{macrocode}
%
% \subsubsection{Slide macros}
%
%
% Switches:\\
% \begin{tabular}{ll}
%   |@bw|           & true if making black and white slides \\
%   |@visible|      & true if visible output to be produced.\\
%   |@makingslides| & true if making a slide/overlay/note
% \end{tabular}
%
%    \begin{macrocode}
\newif\if@bw
\newif\if@visible
\newif\if@onlyslidesw \@onlyslideswfalse
\newif\if@onlynotesw  \@onlynoteswfalse
\newif\if@makingslides
%    \end{macrocode}
% FMi: |\newifG| replaces |\gdef\@slidesw{T}| stuff
%    \begin{macrocode}
\newifG\ifG@slidesw
%    \end{macrocode}
% Counters\\
% \begin{tabular}{ll}
%  slide   & slide number\\
%  overlay & overlay number for a slide\\
%  note    & note number for a slide
% \end{tabular}
%
%    \begin{macrocode}
\countdef\c@slide=0 \c@slide=0
\def\cl@slide{}
\countdef\c@overlay=1 \c@overlay=0
\def\cl@overlay{}
\countdef\c@note=2 \c@note=0
\def\cl@note{}
%    \end{macrocode}
%  Add these counters explicitly to the `ckpt list' so that the
%  |\include| mechanism works.
% \changes{v2.3u}{1996/05/09}{Make include work: pr/2140(CAR)}
% \changes{v2.3y}{1997/05/09}{Make include work properly: add the
% counters in case some are already in there: pr/2140+2474(CAR)}
% \changes{v2.3v}{1996/05/11}{Do not add page counter here as it is
%   added below(CAR)}
%    \begin{macrocode}
\g@addto@macro\cl@@ckpt{\@elt{slide}\@elt{overlay}\@elt{note}}
\@addtoreset{overlay}{slide}
\@addtoreset{note}{slide}
%    \end{macrocode}
% Redefine page counter to some other number.
% The page counter will always be zero except when putting out an
% extra page for a slide, note or overlay.
%    \begin{macrocode}
\@definecounter{page}
\@addtoreset{page}{slide}
\@addtoreset{page}{note}
\@addtoreset{page}{overlay}

\def\theslide{\@arabic\c@slide}
\def\theoverlay{\theslide-\@alph\c@overlay}
\def\thenote{\theslide-\@arabic\c@note}
%    \end{macrocode}
% \begin{verbatim}
% \@setlimits \LIST \LOW \HIGH
%
%    Assumes that \LIST = RANGE1,RANGE2,...,RANGEn  (n>0)
%    Where RANGEi = j or j-k.
%
%    Then \@setlimits  globally sets
%        (i) \LIST := RANGE2, ... , RANGEn
%       (ii) \LOW  := p
%      (iii) \HIGH := q
%   where either RANGE1 = p-q   or  RANGE1 = p  and  q=p.
%\end{verbatim}
%    \begin{macrocode}
\def\@sl@getargs#1-#2-#3\relax#4#5{\xdef#4{#1}\xdef#5{#2}}
\def\@sl@ccdr#1,#2\relax#3#4{\xdef#3{#1-#1-}\xdef#4{#2}}

\def\@setlimits #1#2#3{\expandafter\@sl@ccdr#1\relax\@sl@gtmp #1%
\expandafter\@sl@getargs\@sl@gtmp\relax#2#3}
%    \end{macrocode}
% \begin{verbatim}
% \onlyslides{LIST} ::=
%  BEGIN
%    @onlyslidesw := true
%    \@doglslidelist :=G LIST,999999,999999
%   if @onlynotesw = true
%     else @onlynotesw := true
%          \@doglnotelist :=G LIST,999999,999999
%   fi
%   message: Only Slides LIST
%  END
%\end{verbatim}
%    \begin{macrocode}
\def\onlyslides#1{\@onlyslideswtrue
   \gdef\@doglslidelist{#1,999999,999999}%
   \if@onlynotesw \else
      \@onlynoteswtrue\gdef\@doglnotelist{999999,999999}\fi
   \typeout{Only Slides #1}}
%    \end{macrocode}
%\begin{verbatim}
% \onlynotes{LIST} ::=
%  BEGIN
%    @onlynotesw := true
%    \@doglnotelist :=G LIST,999999,999999
%   if @onlyslidesw = true
%     else \@onlyslidesw := true
%          \@doglslidelist{999999,999999}
%   fi
%   message: Only Notes LIST
%  END
%\end{verbatim}
%    \begin{macrocode}
\def\onlynotes#1{\@onlynoteswtrue
   \gdef\@doglnotelist{#1,999999,999999}%
   \if@onlyslidesw \else
      \@onlyslideswtrue\gdef\@doglslidelist{999999,999999}\fi
   \typeout{Only Notes #1}}
%    \end{macrocode}
%\begin{verbatim}
% \setupcounters ::=    (similar to old \blackandwhite #1  ::= )
%    \newpage
%    page counter := 0
%    @bw := T
%    @visible := T
%    if @onlyslidesw = true
%      then  \@doslidelist := \@doglslidelist
%            \@setlimits\@doslidelist\@doslidelow\@doslidehigh
%    fi
%    if @onlynotesw = true
%      then  \@donotelist := \@doglnotelist
%            \@setlimits\@donotelist\@donotelow\@donotehigh
%    fi
%    \normalsize    % Note, this sets font to \rmfamily , which sets
%                     % \@currfont to \rmfamily
%    counter slidenumber := 0
%    counter note        := 0
%    counter overlay     := 0
%    @makingslides       := F  %% \blackandwhite: @makingslides  := T
%                              %%                 input #1
%                              %%                 @makingslides  := F
%\end{verbatim}
%    \begin{macrocode}
\if@compatibility
% In compatibility mode, need to define \verb+\blackandwhite+,
% \verb+\colors+, \verb+\colorslides+, etc.
\def\blackandwhite#1{\newpage\setcounter{page}{0}\@bwtrue\@visibletrue
\if@onlyslidesw \xdef\@doslidelist{\@doglslidelist}%
\@setlimits\@doslidelist\@doslidelow\@doslidehigh\fi
\if@onlynotesw \xdef\@donotelist{\@doglnotelist}%
\@setlimits\@donotelist\@donotelow\@donotehigh\fi
\normalsize\setcounter{slide}{0}\setcounter{overlay}{0}%
\setcounter{note}{0}\@makingslidestrue\input #1\@makingslidesfalse}
%    \end{macrocode}
%\begin{verbatim}
% \colors{COLORS} ::=
%  for \@colortemp := COLORS
%     do \csname \@colortemp \endcsname == \@color{\@colortemp} od
%  if \@colorlist = empty
%     then \@colorlist := COLORS
%     else \@colorlist := \@colorlist , COLORS
%  fi
%\end{verbatim}
%
%    \begin{macrocode}
\def\colors#1{\@for\@colortemp:=#1\do{\expandafter
  \xdef\csname\@colortemp\endcsname{\noexpand\@color{\@colortemp}}}\ifx
  \@colorlist\@empty \gdef\@colorlist{#1}%
    \else \xdef\@colorlist{\@colorlist,#1}\fi}

\def\@colorlist{}
%    \end{macrocode}
%\begin{verbatim}
% \colorslides{FILE} ::=
%    \newpage
%    page counter := 0
%    @bw := F
%    for \@currcolor := \@colorlist
%      do  @visible := T
%          if @onlyslidesw = true
%            then  \@doslidelist := \@doglslidelist
%                  \@setlimits\@doslidelist\@doslidelow\@doslidehigh
%          fi
%          if @onlynotesw = true
%            then  \@donotelist := \@doglnotelist
%                  \@setlimits\@donotelist\@donotelow\@donotehigh
%          fi
%          \normalsize
%          counter slide := 0
%          counter overlay := 0
%          counter note    := 0
%          type message
%          generate color layer output page
%          @makingslides := T
%          input #1
%          @makingslides := F
%      od
%\end{verbatim}
%    \begin{macrocode}
\def\colorslides#1{\newpage\setcounter{page}{0}\@bwfalse
\@for\@currcolor:=\@colorlist\do
{\@visibletrue
\if@onlyslidesw \xdef\@doslidelist{\@doglslidelist}%
\@setlimits\@doslidelist\@doslidelow\@doslidehigh\fi
\if@onlynotesw \xdef\@donotelist{\@doglnotelist}%
\@setlimits\@donotelist\@donotelow\@donotehigh\fi
\normalsize\setcounter{slide}{0}\setcounter{overlay}{0}%
\setcounter{note}{0}\typeout{color \@currcolor}%
\newpage
\begin{huge}%
\begin{center}%
COLOR LAYER\\[.75in]%
\@currcolor
\end{center}%
\end{huge}%
\newpage
\@makingslidestrue
\input #1
\@makingslidesfalse}}
%
\else  %% if@compatibility
%
\def\setupcounters{\newpage\setcounter{page}{0}\@bwtrue\@visibletrue
\if@onlyslidesw \xdef\@doslidelist{\@doglslidelist}%
\@setlimits\@doslidelist\@doslidelow\@doslidehigh\fi
\if@onlynotesw \xdef\@donotelist{\@doglnotelist}%
\@setlimits\@donotelist\@donotelow\@donotehigh\fi
\normalsize\setcounter{slide}{0}\setcounter{overlay}{0}%
\setcounter{note}{0}\@makingslidesfalse}

\AtBeginDocument{\setupcounters}
\fi %% if@compatibility
%    \end{macrocode}
%\begin{verbatim}
% \slide COLORS ::=
%  BEGIN
% \changes{v2.3}{1994/03/16}{Moved \cs{newpage} up front, here and in
%    \cs{note} and \cs{overlay}}
%   \par\break
%   \stepcounter{slide}
%   \setcounter{page}{0}                    % in case of non-slide pages
%   \@slidesw :=G T
%   if @onlyslidesw = true                  % set \@slidesw = T iff
%     then                                  % page to be output
%       while \c@slide > \@doslidehigh
%          do  \@setlimits\@doslidelist\@doslidelow\@doslidehigh  od
%       if \c@slide < \@doslidelow
%         then \@slidesw := F
%       fi
%   fi
%   if \@slidesw = T
%      then \@slidesw :=G F
%           \begingroup
%              if @bw = true
%                then  \@slidesw :=G T
%                else \@color{COLORS}
%                     \if@visible then \@slidesw :=G T \fi
%              fi
%            \endgroup
%  fi
%  if \@slidesw = T
%    then @makingslides  := T
%         \thispagestyle{slide}
%    else \end{slide}
%          \@gobbletoend{slide}
%  fi
% END
%
% \endslide ::=
%  BEGIN
%    \par\break
%  END
%\end{verbatim}
%    \begin{macrocode}
\if@compatibility
\def\slide#1{\stepcounter{slide}\G@slideswtrue\if@onlyslidesw
\@whilenum \c@slide >\@doslidehigh\relax
\do{\@setlimits\@doslidelist\@doslidelow\@doslidehigh}\ifnum
\c@slide <\@doslidelow\relax\G@slideswfalse\fi\fi
\ifG@slidesw
  \G@slideswfalse
% FMi this is only a hack at the moment to get things running.
%  \begingroup
  \if@bw\G@slideswtrue\else
    \@color{#1}\if@visible \G@slideswtrue \fi
  \fi
%  \endgroup
\fi
\ifG@slidesw \newpage\thispagestyle{slide}%
%    \end{macrocode}
%    This will set up the last color specified in the argument to
%    \verb+\slide+ as the current color. If only back and white  slides
%    are prepared \verb+\last@color+ will be empty and effectively
%    \verb+\relax+ will be generated (hopefully).
%
%    We need to reset to a default font at the beginning of a slide.
%    (not done yet).
%    \begin{macrocode}
\csname \last@color \endcsname
%    \end{macrocode}
%    \begin{macrocode}
\else\end{slide}\@gobbletoend{slide}\fi}
%
\else  %% if@compatibility
%
\def\slide{\par\break
\stepcounter{slide}\setcounter{page}{0}\G@slideswtrue\if@onlyslidesw
\@whilenum \c@slide >\@doslidehigh\relax
\do{\@setlimits\@doslidelist\@doslidelow\@doslidehigh}\ifnum
\c@slide <\@doslidelow\relax\G@slideswfalse\fi\fi
\ifG@slidesw
  \G@slideswfalse
% FMi this is only a hack at the moment to get things running.
%  \begingroup
  \if@bw\G@slideswtrue\else
    \if@visible \G@slideswtrue \fi
  \fi
%  \endgroup
\fi
\ifG@slidesw \@makingslidestrue\thispagestyle{slide}%
%    \end{macrocode}
%    This will set up the last color specified in the argument to
%    \verb+\slide+ as the current color. If only back and white  slides
%    are prepared \verb+\last@color+ will be empty and effectively
%    \verb+\relax+ will be generated (hopefully).
%
%    We need to reset to a default font at the beginning of a slide.
%    (not done yet).
%    \begin{macrocode}
\csname \last@color \endcsname
%    \end{macrocode}
%    \begin{macrocode}
\else\end{slide}\@gobbletoend{slide}\fi}
\fi %% if@compatibility

\let\last@color\@empty

\def\endslide{\par\break}
%    \end{macrocode}
%\begin{verbatim}
% \overlay COLORS ::=
%  BEGIN
%   \par\break
%   \stepcounter{overlay}
%   \setcounter{page}{0}                    % in case of non-slide pages
%   \@slidesw :=G T
%   if @onlyslidesw = T                     % set \@slidesw = T iff
%     then                                  % page to be output
%       if \c@slide < \@doslidelow
%         then \@slidesw :=G F
%       fi
%  fi
%  if \@slidesw = T
%    \@slidesw :=G F
%    \begingroup
%      if @bw = true
%          then  \@slidesw :=G T
%          else  \@color{COLORS}
%                \if@visible then \@slidesw :=G T \fi
%      fi
%    \endgroup
%  fi
%  if \@slidesw = T
%     then @makingslides  := T
%          \thispagestyle{overlay}
%     else \end{overlay}
%          \@gobbletoend{overlay}
%  fi
% END
%
% \endoverlay ::=
%  BEGIN
%    \par\break
%  END
%\end{verbatim}
%    \begin{macrocode}
\if@compatibility
\def\overlay#1{\stepcounter{overlay}\G@slideswtrue%
\if@onlyslidesw\ifnum \c@slide <\@doslidelow\relax
\G@slideswfalse\fi\fi
\ifG@slidesw \G@slideswfalse\begingroup\if@bw\G@slideswtrue%
\else\@color{#1}\if@visible \G@slideswtrue\fi\fi\endgroup\fi
\ifG@slidesw \newpage\thispagestyle{overlay}%
\else\end{overlay}\@gobbletoend{overlay}\fi}
%
\else %%if@compatibility
%
\def\overlay{\par\break
  \stepcounter{overlay}%
  \setcounter{page}{0}%
  \G@slideswtrue%
  \if@onlyslidesw\ifnum \c@slide <\@doslidelow\relax
    \G@slideswfalse\fi\fi
  \ifG@slidesw \G@slideswfalse
    \begingroup\if@bw\G@slideswtrue%
               \else\if@visible \G@slideswtrue\fi\fi
    \endgroup\fi
  \ifG@slidesw \@makingslidestrue\thispagestyle{overlay}%
  \else\end{overlay}\@gobbletoend{overlay}\fi}
\fi %%if@compatibility

\def\endoverlay{\par\break}
%    \end{macrocode}
%
% \changes{v2.0d}{1993/11/12}{Removed extra blank.}
%\begin{verbatim}
% \note ::=
%  BEGIN
%   \par\break
%   \stepcounter{note}
%   \setcounter{page}{0}                    % in case of non-slide pages
%   if @bw = T
%     then
%       \@slidesw :=G T
%       if @onlynotesw = true                  % set \@notesw = T iff
%         then                                 % page to be output
%           while \c@slide > \@donotehigh
%              do  \@setlimits\@donotelist\@donotelow\@donotehigh  od
%           if \c@slide < \@donotelow
%             then \@slidesw :=G F
%           fi
%       fi
%     else \@slidesw :=G F
%  fi
%  if \@slidesw = T
%     then @makingslides   := T
%          \thispagestyle{note}
%     else \end{note}
%          \@gobbletoend{note}
%  fi
% END
%
% \endnote ::=
%  BEGIN
%    \par\break
%  END
%\end{verbatim}
%    \begin{macrocode}
\if@compatibility
\def\note{\stepcounter{note}%
   \if@bw
      \G@slideswtrue
      \if@onlynotesw\@whilenum \c@slide >\@donotehigh\relax
      \do{\@setlimits\@donotelist\@donotelow\@donotehigh}\ifnum
        \c@slide <\@donotelow\relax \G@slideswfalse\fi\fi
      \else\G@slideswfalse\fi
      \ifG@slidesw \newpage\thispagestyle{note}\else
      \end{note}\@gobbletoend{note}\fi}
%
\else %%if@compatibility
%
\def\note{\par\break\stepcounter{note}\setcounter{page}{0}%
   \if@bw
      \G@slideswtrue
      \if@onlynotesw\@whilenum \c@slide >\@donotehigh\relax
      \do{\@setlimits\@donotelist\@donotelow\@donotehigh}\ifnum
        \c@slide <\@donotelow\relax \G@slideswfalse\fi\fi
      \else\G@slideswfalse\fi
      \ifG@slidesw \@makingslidestrue\thispagestyle{note}\else
      \end{note}\@gobbletoend{note}\fi}
\fi %%if@compatibility

\def\endnote{\par\break}
%    \end{macrocode}
%\begin{verbatim}
% \@color{COLORS} ::=
%  BEGIN
%   if math mode
%     then type warning
%   fi
%   if @bw
%     then \visible
%     else \invisible
%         for \last@color := COLORS
%          do if \last@color = \@currcolor
%               then \visible
%             fi
%          od
%   fi
%   \ignorespaces
% END
%\end{verbatim}
% FMi: |\last@color| will be used in |\slide| to set up first
%      color if no color is given.
% I suppose that this is much too complicated. |\else\@tempswafalse|
% would produce the same effect I imagine.
%    \begin{macrocode}
\def\@color#1{\@mmodetest
 {\if@bw \@tempswatrue \else \@tempswafalse
   \@for \reserved@a :=#1\do{\ifx\reserved@a\@currcolor\@tempswatrue\fi
                         \let\last@color\reserved@a}\fi
  \if@tempswa \visible \else \invisible \fi
  \ignorespaces}}

\def\@mmodetest#1{\ifmmode\ClassWarning{slides}{Color-changing command
       in math mode has been ignored}\else #1\fi}

\def\invisible{\@mmodetest
  {\if@visible
     \@visiblefalse
     \fontshape\f@shape\selectfont
     \mathversion{invisible}%
   \fi
   \ignorespaces}}

\def\visible{\@mmodetest
  {\if@visible
   \else
     \@visibletrue
%    \end{macrocode}
%    Here is the \LaTeXe{} interface hidden. We use a trick to provide
%    ourselves with a sort of additional attribute without making the
%    current mechanism even larger. The trick is that we denote
%    invisible by putting an uppercase |I| in front of the shape name
%    for invisible shapes and remove it again if we want to become
%    visible.
%    \begin{macrocode}
     \fontshape{\expandafter\@gobble\f@shape}\selectfont
     \mathversion{normal}%
   \fi
   \ignorespaces}}

\def\fontshape#1{\edef\f@shape{\if@visible \else I\fi #1}}
%    \end{macrocode}
%
% \subsection{Macros for font handling}
%
%    We let |\familydefault| point at |\sfdefault|, to make it easier
%    to use the document class slides with packages that set up other
%    fonts.
%    \begin{macrocode}
\renewcommand{\familydefault}{\sfdefault}
%    \end{macrocode}
%
%  \changes{v2.3l}{1994/12/16}{Added the declaration of the lasy font
%    family}
%    The \texttt{latexsym} package, which is needed to be able to access
%    the \LaTeX\ symbol fonts (lasy), sets things up so that for sizes
%    larger then 10 point magnifications of \texttt{lasy10} are
%    used. For slides we want to use magnifications of \texttt{lasy8},
%    so we set up the lasy family here to prevent \LaTeX\ from loading
%    \texttt{Ulasy.fd}.
%    \begin{macrocode}
\DeclareFontFamily{U}{lasy}{}{}
\DeclareFontShape{U}{lasy}{m}{n}{%
      <12><13.82><16.59><19.907><23.89><28.66><34.4><41.28>lasy8
}{}
\DeclareFontShape{U}{lasy}{m}{In}{%
      <13.82><16.59><19.907><23.89><28.66><34.4><41.28>ilasy8
}{}
%    \end{macrocode}
%
%    \begin{macrocode}
\message{picture,}
%    \end{macrocode}
%
%  \subsubsection{Modifications to the picture environment}
%
%  Below are the new definitions of the picture-drawing macros
%  required for SLiTeX.  Only those commands that actually
%  draw something must be changed so that they do not produce
%  any output when the |@visible| switch is false.
%
% \changes{v2.2j}{1994/03/11}{Corrected \cs{@oval}, like previous
%    change to the \LaTeX{} format.}
% \changes{v2.4a}{2016/03/29}{Initialize in \cs{@oval}tests added for
%    latex/4452}
%    \begin{macrocode}
\def\line(#1,#2)#3{\if@visible\@xarg #1\relax \@yarg #2\relax
\@linelen #3\unitlength
\ifnum\@xarg =\z@ \@vline
  \else \ifnum\@yarg =\z@ \@hline \else \@sline\fi
\fi\fi}

\def\vector(#1,#2)#3{\if@visible\@xarg #1\relax \@yarg #2\relax
\@linelen #3\unitlength
\ifnum\@xarg =\z@ \@vvector
  \else \ifnum\@yarg =\z@ \@hvector \else \@svector\fi
\fi\fi}

\def\dashbox#1(#2,#3){%
\leavevmode\if@visible\hb@xt@\z@{\baselineskip \z@
\lineskip \z@
\@dashdim #2\unitlength
\@dashcnt \@dashdim \advance\@dashcnt 200
\@dashdim #1\unitlength\divide\@dashcnt \@dashdim
\ifodd\@dashcnt\@dashdim\z@
\advance\@dashcnt \@ne \divide\@dashcnt \tw@
\else \divide\@dashdim \tw@ \divide\@dashcnt \tw@
\advance\@dashcnt \m@ne
\setbox\@dashbox \hbox{\vrule \@height \@halfwidth \@depth \@halfwidth
\@width \@dashdim}\put(0,0){\copy\@dashbox}%
\put(0,#3){\copy\@dashbox}%
\put(#2,0){\hskip-\@dashdim\copy\@dashbox}%
\put(#2,#3){\hskip-\@dashdim\box\@dashbox}%
\multiply\@dashdim \thr@@
\fi
\setbox\@dashbox \hbox{\vrule \@height \@halfwidth \@depth \@halfwidth
\@width #1\unitlength\hskip #1\unitlength}\@tempcnta\z@
\put(0,0){\hskip\@dashdim \@whilenum \@tempcnta <\@dashcnt
\do{\copy\@dashbox\advance\@tempcnta \@ne }}\@tempcnta\z@
\put(0,#3){\hskip\@dashdim \@whilenum \@tempcnta <\@dashcnt
\do{\copy\@dashbox\advance\@tempcnta \@ne }}%
\@dashdim #3\unitlength
\@dashcnt=\@dashdim \advance\@dashcnt 200
\@dashdim #1\unitlength\divide\@dashcnt \@dashdim
\ifodd\@dashcnt \@dashdim=\z@
\advance\@dashcnt \@ne \divide\@dashcnt \tw@
\else
\divide\@dashdim \tw@ \divide\@dashcnt \tw@
\advance\@dashcnt \m@ne
\setbox\@dashbox\hbox{\hskip -\@halfwidth
\vrule \@width \@wholewidth
\@height \@dashdim}\put(0,0){\copy\@dashbox}%
\put(#2,0){\copy\@dashbox}%
\put(0,#3){\lower\@dashdim\copy\@dashbox}%
\put(#2,#3){\lower\@dashdim\copy\@dashbox}%
\multiply\@dashdim \thr@@
\fi
\setbox\@dashbox\hbox{\vrule \@width \@wholewidth
\@height #1\unitlength}\@tempcnta\z@
\put(0,0){\hskip -\@halfwidth \vbox{\@whilenum \@tempcnta <\@dashcnt
\do{\vskip #1\unitlength\copy\@dashbox\advance\@tempcnta \@ne }%
\vskip\@dashdim}}\@tempcnta\z@
\put(#2,0){\hskip -\@halfwidth \vbox{\@whilenum \@tempcnta <\@dashcnt
\relax\do{\vskip #1\unitlength\copy\@dashbox\advance\@tempcnta \@ne }%
\vskip\@dashdim}}}\fi\@makepicbox(#2,#3)}
%    \end{macrocode}
% (re)declare these booleans as they not defined in old format
% (or with latexrelease package)
%    \begin{macrocode}
\newif\if@ovvline \@ovvlinetrue
\newif\if@ovhline \@ovhlinetrue
%    \end{macrocode}
%    \begin{macrocode}
\def\@oval(#1,#2)[#3]{\if@visible\begingroup \boxmaxdepth \maxdimen
  \@ovttrue \@ovbtrue \@ovltrue \@ovrtrue
%    \end{macrocode}
%    \begin{macrocode}
  \@ovvlinefalse \@ovhlinefalse
%    \end{macrocode}
%    \begin{macrocode}
  \@tfor\reserved@a :=#3\do
     {\csname @ov\reserved@a false\endcsname}%
  \@ovxx#1\unitlength \@ovyy #2\unitlength
%    \end{macrocode}
%    \begin{macrocode}
  \@tempdimb \ifdim \@ovyy >\@ovxx \@ovxx \@ovvlinetrue
  \else \@ovyy \ifdim \@ovyy =\@ovxx \else \@ovhlinetrue \fi\fi
%    \end{macrocode}
%    \begin{macrocode}
  \advance \@tempdimb -2\p@
  \@getcirc \@tempdimb
  \@ovro \ht\@tempboxa \@ovri \dp\@tempboxa
  \@ovdx\@ovxx \advance\@ovdx -\@tempdima \divide\@ovdx \tw@
  \@ovdy\@ovyy \advance\@ovdy -\@tempdima \divide\@ovdy \tw@
%    \end{macrocode}
%    \begin{macrocode}
  \ifdim \@ovdx >\z@ \@ovhlinetrue \fi
  \ifdim \@ovdy >\z@ \@ovvlinetrue \fi
%    \end{macrocode}
%    \begin{macrocode}
  \@circlefnt \setbox\@tempboxa
  \hbox{\if@ovr \@ovvert32\kern -\@tempdima \fi
  \if@ovl \kern \@ovxx \@ovvert01\kern -\@tempdima \kern -\@ovxx \fi
  \if@ovt \@ovhorz \kern -\@ovxx \fi
  \if@ovb \raise \@ovyy \@ovhorz \fi}\advance\@ovdx\@ovro
  \advance\@ovdy\@ovro \ht\@tempboxa\z@ \dp\@tempboxa\z@
  \@put{-\@ovdx}{-\@ovdy}{\box\@tempboxa}%
  \endgroup\fi}

\def\@circle#1{\if@visible \begingroup \boxmaxdepth \maxdimen
   \@tempdimb #1\unitlength
   \ifdim \@tempdimb >15.5\p@\relax \@getcirc\@tempdimb
      \@ovro\ht\@tempboxa
     \setbox\@tempboxa\hbox{\@circlefnt
      \advance\@tempcnta\tw@ \char \@tempcnta
      \advance\@tempcnta\m@ne \char \@tempcnta \kern -2\@tempdima
      \advance\@tempcnta\tw@
      \raise \@tempdima \hbox{\char\@tempcnta}\raise \@tempdima
        \box\@tempboxa}\ht\@tempboxa\z@ \dp\@tempboxa\z@
      \@put{-\@ovro}{-\@ovro}{\box\@tempboxa}%
   \else  \@circ\@tempdimb{96}\fi\endgroup\fi}

%    \end{macrocode}
%
% \changes{v2.0d}{1993/11/12}{Removed extra blank.}
%    \begin{macrocode}
\def\@dot#1{%
  \if@visible\@tempdimb #1\unitlength \@circ\@tempdimb{112}\fi}
%    \end{macrocode}
% \changes {v2.3m}{1994/03/20}{(DPC) Remove old \cs{@iframebox} and
%    \cs{fbox} defn}
% \changes {v2.3m}{1994/03/20}{(DPC) Add \cs{@frameb@x} defn.}
%    \begin{macrocode}
\def\@frameb@x#1{%
  \@tempdima\fboxrule
  \advance\@tempdima\fboxsep
  \advance\@tempdima\dp\@tempboxa
  \leavevmode
  \hbox{%
    \lower\@tempdima\hbox{%
      \vbox{%
        \if@visible\hrule\@height\else\vskip\fi\fboxrule
        \hbox{%
          \if@visible\vrule\@width\else\hskip\fi\fboxrule
          #1%
          \vbox{%
            \vskip\fboxsep
            \box\@tempboxa
            \vskip\fboxsep}%
          #1%
          \if@visible\vrule\@width\else\hskip\fi\fboxrule}%
        \if@visible\hrule\@height\else\vskip\fi\fboxrule}}}}

%    \end{macrocode}
%
%    \begin{macrocode}
\long\def\frame#1{\if@visible\leavevmode
\vbox{\vskip-\@halfwidth\hrule \@height\@halfwidth \@depth \@halfwidth
  \vskip-\@halfwidth\hbox{\hskip-\@halfwidth \vrule \@width\@wholewidth
  \hskip-\@halfwidth #1\hskip-\@halfwidth \vrule \@width \@wholewidth
  \hskip -\@halfwidth}\vskip -\@halfwidth\hrule \@height \@halfwidth
  \@depth \@halfwidth\vskip -\@halfwidth}\else #1\fi}
%    \end{macrocode}
%
% \changes{v2.0d}{1993/11/12}{Corrected \cs{@math} to \cs{m@th} in
%    definition of \cs{underline}.}
%
%    \begin{macrocode}
\message{mods,}
%    \end{macrocode}
%
%
%  \subsubsection{Other modifications to \TeX{} and \LaTeX{} commands}
%
% |\rule|
%    \begin{macrocode}
\def\@rule[#1]#2#3{\@tempdima#3\advance\@tempdima #1\leavevmode
 \hbox{\if@visible\vrule
  \@width#2 \@height\@tempdima \@depth-#1\else
\vrule \@width \z@ \@height\@tempdima \@depth-#1\vrule
 \@width#2 \@height\z@\fi}}

% \_  (Added 10 Nov 86)

\def\_{\leavevmode \kern.06em \if@visible\vbox{\hrule \@width.3em}\else
   \vbox{\hrule \@height \z@ \@width.3em}\vbox{\hrule \@width \z@}\fi}
%    \end{macrocode}
%\begin{verbatim}
% \overline, \underline, \frac and \sqrt
%
% \@mathbox{STYLE}{BOX}{MTEXT} : Called in math mode, typesets MTEXT and
%   stores result in BOX, using STYLE.
%
% \@bphant{BOX}    : Creates a phantom with dimensions BOX.
% \@vbphant{BOX}   : Creates a phantom with ht of BOX and zero width.
% \@hbphant{BOX}   : Creates a phantom with width of BOX
%                    and zero ht & dp.
% \@hvsmash{STYLE}{MTEXT} : Creates a copy of MTEXT with zero height and
%                           width in STYLE.
%\end{verbatim}
%    \begin{macrocode}
\def\@mathbox#1#2#3{\setbox#2\hbox{$\m@th#1{#3}$}}

\def\@vbphantom#1{\setbox\tw@\null \ht\tw@\ht #1\dp\tw@\dp #1%
   \box\tw@}

\def\@bphantom#1{\setbox\tw@\null
   \wd\tw@\wd #1\ht\tw@\ht #1\dp\tw@\dp #1%
   \box\tw@}

\def\@hbphantom#1{\setbox\tw@\null \wd\tw@\wd #1\ht\tw@\z@ \dp\tw@\z@
   \box\tw@}

\def\@hvsmash#1#2{\@mathbox#1\z@{#2}\ht\z@\z@ \dp\z@\z@ \wd\z@\z@
   \box\z@}

\def\underline#1{\relax\ifmmode
  \@xunderline{#1}\else $\m@th\@xunderline{\hbox{#1}}$\relax\fi}

\def\@xunderline#1{\mathchoice{\@xyunderline\displaystyle{#1}}%
   {\@xyunderline
    \textstyle{#1}}{\@xyunderline\scriptstyle{#1}}{\@xyunderline
      \scriptscriptstyle{#1}}}

\def\@xyunderline#1#2{%
   \@mathbox#1\@smashboxa{#2}\@hvsmash#1{\copy\@smashboxa}%
   \if@visible \@hvsmash#1{\@@underline{\@bphantom\@smashboxa}}\fi
  \@mathbox#1\@smashboxb{\@@underline{\box\@smashboxa}}%
   \@bphantom\@smashboxb}

\let\@@overline=\overline

\def\overline#1{\mathchoice{\@xoverline\displaystyle{#1}}{\@xoverline
    \textstyle{#1}}{\@xoverline\scriptstyle{#1}}{\@xoverline
      \scriptscriptstyle{#1}}}

\def\@xoverline#1#2{%
   \@mathbox#1\@smashboxa{#2}\@hvsmash#1{\copy\@smashboxa}%
   \if@visible \@hvsmash#1{\@@overline{\@bphantom\@smashboxa}}\fi
   \@mathbox#1\@smashboxb{\@@overline{\box\@smashboxa}}%
   \@bphantom\@smashboxb}
%    \end{macrocode}
%
% \changes{v2.0b}{1993/04/14}{Corrected \cs{frac} command.}
% \changes{v2.0d}{1993/11/12}{Removed \cs{vcenter} in \cs{@frac}.}
%
%\begin{verbatim}
% \@frac {STYLE}{DENOMSTYLE}{NUM}{DEN}{FONTSIZE} :
%   Creates \frac{NUM}{DENOM}
%   in style STYLE with NUM and DENOM in style DENOMSTYLE
%   FONTSIZE should be \textfont \scriptfont or \scriptscriptfont
%\end{verbatim}
%    Added a group around the first argument of |\frac| to prevent
%    changes (for example font changes) to modify the contents of the
%    second argument.
% \changes{v2.1c}{1993/12/13}{Added group around first arg.}
%    \begin{macrocode}
\def\frac#1#2{\mathchoice
   {\@frac\displaystyle\textstyle{#1}{#2}\textfont}{\@frac
         \textstyle\scriptstyle{#1}{#2}\textfont}{\@frac
         \scriptstyle\scriptscriptstyle{#1}{#2}\scriptfont}{\@frac
         \scriptscriptstyle\scriptscriptstyle{#1}{#2}\scriptscriptfont}}

\def\@frac#1#2#3#4#5{%
   \@mathbox#1\@smashboxc{{\begingroup#3\endgroup\over#4}}%
   \setbox\tw@\null
   \ht\tw@ \ht\@smashboxc
   \dp\tw@ \dp\@smashboxc
   \wd\tw@ \wd\@smashboxc
   \box\if@visible\@smashboxc\else\tw@\fi}

\def\r@@t#1#2{\setbox\z@\hbox{$\m@th#1\@xysqrt#1{#2}$}%
  \dimen@\ht\z@ \advance\dimen@-\dp\z@
  \mskip5mu\raise.6\dimen@\copy\rootbox \mskip-10mu\box\z@}
%    \end{macrocode}
% \changes{v2.3w}{1996/05/15}{Removed use of obsolete command
%                             \cs{@@sqrt} (CAR)}
%    \begin{macrocode}
\def\sqrt{\@ifnextchar[{\@sqrt}{\@xsqrt}}
\def\@sqrt[#1]{\root #1\of}
\def\@xsqrt#1{\mathchoice{\@xysqrt\displaystyle{#1}}{\@xysqrt
     \textstyle{#1}}{\@xysqrt\scriptstyle{#1}}{\@xysqrt
    \scriptscriptstyle{#1}}}
\def\@xysqrt#1#2{\@mathbox#1\@smashboxa{#2}\if@visible
    \@hvsmash#1{\sqrtsign{\@bphantom\@smashboxa}}\fi
    \phantom{\sqrtsign{\@vbphantom\@smashboxa}}\box\@smashboxa}

\newbox\@smashboxa
\newbox\@smashboxb
\newbox\@smashboxc
%    \end{macrocode}
%
% array and tabular environments: changes to `\verb+|+', |\hline|,
% |\cline|, and |\vline|,
% added 8 Jun 88
%    \begin{macrocode}
\def\@arrayrule{\if@visible\@addtopreamble{\hskip -.5\arrayrulewidth
   \vrule \@width \arrayrulewidth\hskip -.5\arrayrulewidth}\fi}
%    \end{macrocode}
%
% \changes{v2.3t}{1996/01/31}{Change in \cs{cline} calling interface}
%    \begin{macrocode}
\def\cline#1{\if@visible\@cline#1\@nil\fi}

\def\hline{\noalign{\ifnum0=`}\fi
    \if@visible \hrule \@height \arrayrulewidth
      \else \hrule \@width \z@
    \fi
    \futurelet \reserved@a\@xhline}

\def\vline{\if@visible \vrule \@width \arrayrulewidth
            \else \vrule \@width \arrayrulewidth \@height \z@
           \@depth \z@ \fi}
%    \end{macrocode}
%
%    \begin{macrocode}
\message{output,}
%    \end{macrocode}
%
% \subsubsection{Changes to \LaTeX{} output routine}
%
%\begin{verbatim}
%  \@makecol ==
%    BEGIN
% % Following test added for slides to check if extra page
%     if @makingslides = T
%     then if \c@page > 0
%             then if \c@note > 0
%                     then type 'Note \thenote too long.'
%                     else if \c@overlay > 0
%                            then type 'Overlay \theoverlay too long.'
%                            else type 'Slide \theslide too long'
%     fi     fi     fi     fi
%     ifvoid \insert\footins
%        then  \@outputbox := \box255
%        else  \@outputbox := \vbox {\unvbox255
%                                    \vskip \skip\footins
%                                    \footnoterule
%                                    \unvbox\@footinsert
%                                   }
%    fi
%    \@freelist :=G \@freelist * \@midlist
%    \@midlist  :=G empty
%    \@combinefloats
%    \@outputbox := \vbox to \@colht{\boxmaxdepth := \maxdepth
%                                     \vfil     %%\vfil added for slides
%                                     \unvbox\@outputbox
%                                     \vfil }   %%\vfil added for slides
%    \maxdepth :=G \@maxdepth
%    END
%\end{verbatim}
% FMi simple hack to allow none centered slides Should be revised
% of course.
%    \begin{macrocode}
\let\@topfil\vfil

\def\@makecol{\if@makingslides\ifnum\c@page>\z@ \@extraslide\fi\fi
\ifvoid\footins \setbox\@outputbox\box\@cclv \let\@botfil\vfil
   \else\let\@botfil\relax\setbox\@outputbox
     \vbox{\unvbox\@cclv\vfil
           \vskip\skip\footins\footnoterule\unvbox\footins\vskip
            \z@ plus.1fil\relax}\fi
  \xdef\@freelist{\@freelist\@midlist}\gdef\@midlist{}\@combinefloats
     \setbox\@outputbox\vbox to\@colht{\boxmaxdepth\maxdepth
        \@topfil\unvbox\@outputbox\@botfil}\global\maxdepth\@maxdepth}

\def\@extraslide{\ifnum\c@note>\z@
    \ClassWarning{slides}{Note \thenote\space too long}\else
     \ifnum\c@overlay>\z@
        \ClassWarning{slides}{Overlay \theoverlay\space too long}\else
        \ClassWarning{slides}{Slide \theslide\space too long}\fi\fi}
%    \end{macrocode}
%
%    \begin{macrocode}
\message{init}
%    \end{macrocode}
%
%
% \subsubsection{Special \SLiTeX{} initializations}
%
%FMi why not allow for ref's ?
%    \begin{macrocode}
%   \nofiles

\@visibletrue
%</cmd>
%    \end{macrocode}
%
%
% \Finale
%
\endinput