There is no way to insert newlines in the mathtext part of the string
(by that I mean between the '$'). However, you can put newline
characters outside of '$'. It gets a bit hairy because of Python's
string escaping rules, but you could do something like:
$\\alpha=%G$\n$\\beta=%G$
Note
I dont think newlines are supported this way in tex. Here's an example:
\documentclass[]{article}
\begin{document}
$a=e^{i\pi}\\x=y$
$$a=e^{i\pi}\\x=y$$
\begin{eqnarray}
a = \frac{e^{i\pi}}{e^{-i\pi}} \\
= e^{i2\pi}
\end{eqnarray}
\end{document}
The first treats the newline as if it
