\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amssymb}
+\usepackage{bm}
\usepackage{ae}
\usepackage{aecompl}
\usepackage[dvips]{graphicx}
\newcommand{\RM}[1]{\MakeUppercase{\romannumeral #1{}}}
% vectors are simply represented by bold font characters
-\renewcommand{\vec}[1]{{\bf #1{}}}
+\renewcommand{\vec}[1]{{\bm #1{}}}
%
% theorem environment