Conflict between MathTime Pro 2 and refcheck

Question

The following MWE shows the problem:

\documentclass{article}
\usepackage{amsmath}
\usepackage[lite]{mtpro2}
\usepackage{refcheck}

\begin{document}
\begin{align}
  a & \leq b
\end{align}
\end{document}

And I get a ! Missing $ inserted.. The problem disappears when refcheck is not used, or when mtpro2 is not used.

Does anyone sees a way to use both packages simultaneously?

Answer 1

mtpro2 redefines \{ and \} in an incompatible way with respect to the usual LaTeX setting. It seems that restoring the commands to the right definition (after loading mtpro2) fixes the issue.

The problem might present itself also without refcheck, because the redefinition performed by mtpro2 doesn't allow \{ and \} to be used in text mode.

\documentclass{article}
\usepackage{amsmath}
\usepackage{refcheck}
\usepackage[lite]{mtpro2}

\DeclareRobustCommand\{{\ifmmode\lbrace\else\textbraceleft\fi}
\DeclareRobustCommand\}{\ifmmode\rbrace\else\textbraceright\fi}

\begin{document}
Braces \{in text\}

\begin{align}
  a & \leq b
\end{align}
\end{document}