%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 8-6-1 on page 499.
%%
%% Copyright (C) 2004 Frank Mittelbach, Michel Goossens,
%%    Johannes Braams, David Carlisle, and Chris Rowley
%%
%% 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.
%%

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

\StartShownPreambleCommands
\usepackage{amsmath}
\StopShownPreambleCommands
\begin{document}
\begin{gather}
  \text{Also, if } \Delta_{\text{max up}}
           = \Delta_{\text{min down}} \notag \\
  \text{(for all ups and downs) then} \notag \\
  \Delta_{\text{sum of ups}}
           = \Delta_{\text{sum of downs}}
\end{gather}
\end{document}