\RequirePackage{ifthen}
\renewcommand{\nomgroup}[1]{%
\ifthenelse{\equal{#1}{R}}{\item[\textbf{Roman symbols}]}{%
\ifthenelse{\equal{#1}{G}}{\item[\textbf{Greek symbols}]}{
\ifthenelse{\equal{#1}{O}}{\item[\textbf{Operators}]}{}}}}
%
\newcommand{\nomunit}[1]{%
\renewcommand{\nomentryend}{\hspace*{\fill}#1}}
