%% 
%%  Ein Beispiel der DANTE-Edition
%%  Mathematiksatz mit LaTeX
%%  3. Auflage
%%  Beispiel 05-02-1 auf Seite 79.
%%  Copyright (C) 2018 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.
%% 
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\documentclass[10pt]{screxa}
\pagestyle{empty}
\setlength\textwidth{352.81416pt}
\setlength\parindent{0pt}
\setcounter{equation}{0}
\renewcommand\theequation{5.\arabic{equation}}
%StartShownPreambleCommands
\usepackage{xcolor,amsmath,amscd}
%StopShownPreambleCommands
\begin{document}
\[ \color{magenta}\left(\prod^n_{\, j=1}\hat{x}_j\right)H_c=%
     \frac{1}{2}\hat{k}_{ij}\det\widehat{\mathbf{K}}(i|i) \]

\begin{align}\color{blue}
\begin{CD}
  R\times S\times T @>\text{restriction}>> S\times T \\
        @VprojVV                            @VVprojV \\
  R\times S         @<<\text{\textcolor{red}{inclusion}}<   S
\end{CD}
\end{align}
\end{document}