%%
%% The LaTeX Companion, 2ed (second printing August 2004)
%%
%% Example 8-6-4 on page 501.
%%
%% 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}
%% Low-level TeX needed here to cancel
%% the old definition of \csc:
\let \csc \relax
\DeclareMathOperator\csc{cosec}
\newcommand\calQ{\mathcal{Q}}
\StopShownPreambleCommands
\begin{document}
\[ \varlimsup_{n\to\infty} \calQ (u_n, u_n - u^{\#})
   \ge \csc (\calQ' (u^{\#}))                     \]
\end{document}