# Inconsistent footnotemark sizes amsart

The footnote symbold is the main body of the text sometimes have different sizes (heights?) when using amsart.

MWE:

\documentclass{amsart}
\begin{document}
A\footnote{1}\textsuperscript{,}\footnote{1}
\end{document}


produces:

Why is the second footnote 2 larger than the first footnote 1?

How can I get rid of this?

PS: Using \documentclass{article} instead of \documentclass{amsart} produces the desired result:

PPS: To answer David Carlisle's question:

a minimal(?) working example when adding \sbox0{$$} once at the start of the document is not sufficient: \documentclass{amsart} \begin{document} \sbox0{$$}
A\footnote{1
\textsuperscript{a} %this textsuperscript inside a footnote causes the problem?
}

B%
\footnote{2}\textsuperscript{, \!}\unskip%
\footnote{3}.
\end{document}


produces:

The people at AMS forgot \check@mathfonts before using \sf@size. The definition of \@makefnmark is

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


but \sf@size can have an unpredictable meaning if not set by \check@mathfonts.

Workaround: patch the macro to do the check.

\documentclass{amsart}
\usepackage{etoolbox}

\makeatletter
\patchcmd{\@makefnmark}{\fontsize}{\check@mathfonts\fontsize}{}{}
\makeatother

\begin{document}

A\footnote{1}\textsuperscript{,}\footnote{1}

\end{document}


You need to make sure there is some use of math before the first use of \textsuperscript

You can use a throw-away empty math list in an \sbox if there is no real math at the start of the document.

You should probably report this to the AMS

\documentclass{amsart}

\begin{document}
\sbox0{$$} A\footnote{1}\textsuperscript{,}\footnote{1} \end{document}  • It is not sufficient to have it once at the start of the document I think. Directly in front of the footnote works fine – Jakob Jan 9 at 2:12 • @Jakob really? that's odd, can you add an example to your question or this answer where once isn't enough (for all normalsize footnotes)? I'm raising this with the AMS so it would be good to get a full spec of the problem.... – David Carlisle Jan 9 at 7:48 • @ David Carlisle: I added an example to the PPS of my question. Thank you for raising this with AMS! – Jakob Jan 13 at 19:08 • @Jakob oh yes you need to initialise the math sizes at every text size do \sbox0{$$ \footnotesize } probably works (I'll do a real check later) – David Carlisle Jan 13 at 20:07
• @Jakob oh no disaster I don't mind losing the tick in general, but losing it to egreg... :-) – David Carlisle Jan 13 at 21:24