\newcommand{\hsmash}{\relax
  \ifmmode\expandafter\mathpalette\expandafter\mathHSMASH
  \else\expandafter\makeHSMASH\fi}
\newcommand{\mathHSMASH}[2]{%
 #1 #2}
\newcommand{\makeHSMASH}[1]{%
 #1}
\newcommand{\empset}{\mbox{$\emptyset$}}
\newcommand{\uniset}{\mbox{${\cal U}$}}
\newcommand{\codeinline}[2]{ \mbox{\tt #2}}
