%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 8-3-5 on page 488.
%%
%% 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{135.0pt}

\StartShownPreambleCommands
\usepackage{amsmath}
\StopShownPreambleCommands
\begin{document}
\begin{gather}
  \sum_{\substack{0 \le i \le m \\ 0 < j < n}} P(i, j) \\
  \sum_{\begin{subarray}{l}  i \in \Lambda   \\
                             0 \le i \le m   \\
                             0 < j < n
        \end{subarray}}  P(i, j)
\end{gather}
\end{document}
