\documentclass[a4paper,12pt]{article}
\usepackage{epic, eepic}

\usepackage{amsmath, amssymb, hymcbk, xspace}
\usepackage{euscript,  array}
\usepackage[T1]{fontenc}
%\usepackage{tipa1}
%\usepackage{calc, wasysym, textcomp, ulsy}

\begin{document}
\pagestyle{empty}


\setlength{\unitlength}{1mm}
\begin{picture}(100,30)

% représentations de la symétrie d'axe L  

\allinethickness{.2mm}\drawline(50,2)(50,28)  
\put(27,15){\circle*{.5}}\put(73,15){\circle*{.5}}\dashline{2}(27,15)(73,15)  
\put(27,14){\makebox(0,0)[t]{$M$}}\put(73,14){\makebox(0,0)[t]{$M'$}}  
\put(85,25){\makebox(0,0)[t]{$M'= s_{\Li}(M)$}}\put(53,2){\makebox(0,0)[b]{\Li}}


\end{picture}
  

\end{document}

%%% Local Variables: 
%%% mode: latex
%%% TeX-master: t
%%% End: 
