# Put subscript text below text and align

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}


You can keep the default centre alignment of \substack and play around with \hphantoms and math overlaps (using mathtools) or use a left-aligned \subarray:

\documentclass{article}

\usepackage{mathtools}

\begin{document}

$AF_{\substack{m = 1 / 3 \\ n = 1.9 - 2}} \qquad AF_{\substack{ m = \mathrlap{1 / 3}\hphantom{1.9 - 2} \\ \hphantom{m}\mathllap{n} = 1.9 - 2 }} \qquad AF_{\subarray{l} m = 1 / 3 \\ \hphantom{m}\mathllap{n} = 1.9 - 2 \endsubarray}$

\end{document}


If you wish to stack the subscript under AF, then you can use \mathop{AF}_{<substack>}.