4
4
\usepackage{amssymb,amsmath}
5
5
\usepackage{ifxetex,ifluatex}
6
6
\usepackage{fixltx2e} % provides \textsubscript
9
7
% use upquote if available, for straight quotes in verbatim environments
10
8
\IfFileExists{upquote.sty}{\usepackage{upquote}}{}
11
9
\ifnum 0\ifxetex 1\fi\ifluatex 1\fi=0 % if pdftex