%%
%% The LaTeX Companion, 3ed
%%
%% Example 11-8-2 on page II-210 in "Mathematical symbol classes".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% 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.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3examargin}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}

  % Shorten the vertical size of the example ...
  \AtBeginDocument{%
    \setlength\abovedisplayskip{.2\abovedisplayskip}%
    \setlength\belowdisplayskip{.2\belowdisplayskip}%
  }

%StartShownPreambleCommands
\thinmuskip=10mu \medmuskip=17mu \thickmuskip=30mu
%StopShownPreambleCommands

\begin{document}
\[   a  -  b  =  -\max \{ x , y \}   \]
\end{document}