I am trying to put the subscript text {m=1/3\\n=1.9-2}
below the text AF and then align the two lines at the "=" sign. Can you assist me in accomplishing this task?
CODE
\documentclass{article}
\usepackage{amsmath}
\usepackage{calc}
\pagestyle{empty}
\begin{document}
\begin{equation*}
AF_{\substack{m=1/3\\n=1.9-2}}
\end{equation*}
\end{document}