ref: e0bfd148e29346f9fb824ea0c6ac86b5870836ce
dir: /sys/src/cmd/python/Doc/tests/math.tex/
\documentclass{howto}
\title{Test of python.sty with math}
\begin{document}
\maketitle
\section{Subscripts in Math Mode}
This contains an inline formula containing a subscript: $H_20$.
This display doesn't make sense, but contains a subscript as well:
$$\sum_1^2 = a_x$$
\end{document}