Math in paper title is wrong size (too small)

The title of my paper contains a math mode expression. Usually this renders correctly, but with the style file I am using for the proceedings in which it will appear, the math mode part appears in normal-size font while the rest of the title is title-size, making the math part look very small. This also happens in section headings.

The style file is here: http://www.sheridanprinting.com/typedept/sig-alternate-2013.cls

Minimal working example:

\documentclass{sig-alternate-2013}
\begin{document}
\title{Proving that $1 > 0$}
\maketitle
\section{Proving that $1 > 0$}
\end{document}

Any advice as to how to to fix this would be great, thank you.