%% 
%%  An UIT Edition example
%% 
%%  Example 09-03-1 on page 168.
%% 
%%  Copyright (C) 2010 Herbert Voss
%% 
%%  It may be distributed and/or modified under the conditions
%%  of the LaTeX Project Public License, either version 1.3
%%  of this license or (at your option) any later version.
%% 
%%  See http://www.latex-project.org/lppl.txt for details.
%% 
%% 
%% ==== 
% Show page(s) 1
%% 
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{375.57637pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\setcounter{equation}{0}
\renewcommand\theequation{9.\arabic{equation}}
\StartShownPreambleCommands
\usepackage{amsmath,amscd}
\StopShownPreambleCommands
\begin{document}
\begin{align}
\begin{CD}
  R\times S\times T @>\text{restriction}>> S\times T \\
  @V\text{proj}VV                          @VV\text{proj}V \\
  R\times S         @<<\text{inclusion}<        S
\end{CD}
\end{align}
\end{document}
