Using \textsuperscript to put commas between consecutive footnotes in amsart document

Question

I'm trying to insert a comma between consecutive footnote markers in an amsart document. I'm trying to do this without using the footmisc package, since for some reason it causes the footnotes in my document to be over-indented. (I'm also using the setspace package, which seems to contribute to this over-indenting.)

\textsuperscript seems like a nice solution for the few instances I need to deal with. But for some reason it results in the second footnote marker being enlarged. See, e.g.,

\documentclass{amsart}
\begin{document}
No comma.\footnote{One.}\footnote{Two.} 
Comma, but with font enlargement.\footnote{One.}\textsuperscript{,}\footnote{Two.}
\end{document}

This works fine if I use \documentclass{article}, but with amsart I get the enlargement. Any ideas on how I can fix this?

Answer 1

Seems, as David Carlisle said, like a bug in amsart. You can use the following definition of \@makefnmark in the preamble of your document to get the smaller size in the document:

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

A complete example:

\documentclass{amsart}

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

\begin{document}
No comma.\footnote{One.}\footnote{Two.} 
Comma, without font enlargement.\footnote{One.}\textsuperscript{,}\footnote{Two.}
\end{document}

Answer 2

I think this could count as a bug in amsart, but it looks like the first time math is used the math font sizes are readjusted. Footnote markers change from 6pt to 7pt. If you add some mathematics at the beginning of the document, even hidden such as

\setbox0\hbox{$s$}

then a consistent (the larger) size is used throughout.