Alexandru Scorpan から texhax メーリングリスト宛のメール:

I don't know if you know, but I though I'd let you know:
ftp://ftp.ams.org/pub/tex/amsltx2.zip

It's funny though that they haven't fixed their \footnote bug, which in
all AMS classes types the footnote mark in the last size used in math
mode.

To see it in action, simply typeset

\documentclass{amsart}
\begin{document}
\Huge $G$
\normalsize Aha\footnote{Wow!}
\end{document}

\makeatletter
\def\@makefnmark{%
\leavevmode
\raise.9ex\hbox{\check@mathfonts
\fontsize\sf@size\z@\normalfont%
\@thefnmark}%
}
\makeatother

I think this fix is due to F. Mittelbach.

~-- Alex