%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-1-12 on page I-266 in "Vertical spacing and page breaks".
%%
%% 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{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{159.0pt}
\sloppy %as the column in the book is so small
%StartShownPreambleCommands
\usepackage[includedisplayed]{enumitem}
\setlist{noitemsep,listparindent=1em,partopsep=0pt,
         topsep=4pt plus 1pt minus 1pt}
%StopShownPreambleCommands

\begin{document}
Now we get the reduced spacing
\begin{center}  here! \end{center}
And this applies to all other display environments too.
\end{document}