There is an error message which I do not understand when I use amsart
in conjunction with fontspec
. The math text in the abstract seems to be deemed too small?
The error is
\textfont 6 is undefined (character =).
Here is a minimal working example:
\documentclass{amsart}
\title{T}\author{A}
\usepackage{fontspec}
\begin{document}
\begin{abstract}
$a=b$
\end{abstract}
\maketitle
\end{document}
Best Answer
It seems to be a bug in the compatibility of
fontspec
with the AMS classes. The problem happens when a font size changing command such as\Small
is issued (such a command is defined byamsart
andamsbook
to change font size relative to the current font size).Apparently, the
legacymaths
symbol font doesn't get defined, and this upsetsamsart
or, more precisely, the font size changing commands.The solution is to call
(which is done by
mathspec
, so Alan Munn's advice works) or to define the required symbol font: