%%
%%  An UIT Edition example
%%
%%  Example 10-10-3 on page 224.
%%
%%  Copyright (C) 2010 Herbert Voss
%%
%%  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.
%%
%%
%% ====
% Show page(s) 1
%%
\documentclass[]{exaarticle}
\pagestyle{empty}
\setlength\textwidth{177.70511pt}
\AtBeginDocument{\setlength\parindent{0pt}}
\StartShownPreambleCommands
\usepackage{amsmath}
\def\pM{\ensuremath{\genfrac{}{}{0pt}{}{+}%
   {\scriptstyle(\kern-1pt-\kern-1pt)}}}
\StopShownPreambleCommands
\begin{document}
{\Large$\pM$}\\   $y=\pM\cdots$
\end{document}