bm and pxfonts conflict in beamer

Question

This is pretty much the same question as No room for a new \mathgroup, with the difference that the proposed solutions do not work when using the beamer class.

The code:

\documentclass{beamer}
 \usepackage{pxfonts}
 \usepackage{bm}  

\begin{document}
  \begin{frame}
    $\frac{1}{2}$
  \end{frame}
\end{document}

gives a no room for a new \mathgroup error.

Is this solvable?

Answer 1

Yes: you're loading several useless math alphabets.

\documentclass{beamer}

\usefonttheme{professionalfonts} % don't bother loading the default fonts

\usepackage{newpxtext,newpxmath}
%\usepackage{pxfonts}
 \usepackage{bm}

\begin{document}
  \begin{frame}
    $\frac{1}{2}$
  \end{frame}
\end{document}

Note that newpxtext and newpxmath seem preferable to pxfonts, if available (it is with an up-to-date TeX distribution).