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

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?

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@barbara beeton: just to call your attention to this question. – Gonzalo Medina Mar 13 '12 at 1:24
@Gonzalo -- curiously, i was not notified about your comment. but i have seen the posting anyhow, and am registering it. – barbara beeton Mar 13 '12 at 17:53
@Gonzalo -- i found the reason i wasn't notified. it's listed as the first point in the "official rules" shown in the first answer to the question When writing a comment, how do I ensure that the person it is addressed to gets notified? if a person hasn't already participated in that question, name matching won't be done. so, if you again find a question that needs ams attention, please send a message to tech-support@ams.org citing tex.stackexchange and the question number. – barbara beeton Mar 13 '12 at 19:38
@barbarabeeton: ah, that explains it. Next time, I'll better send the message. – Gonzalo Medina Mar 13 '12 at 20:16

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}


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Thanks to both answerers. Oddly, whether or not the above solution results in the larger or smaller font size being used (for all foonote marks) seems to depend on the document font size. With the default \documentclass{amsart}, the smaller size is used. But with \documentclass[12pt]{amsart}, the larger size is used. So for a 12pt document these two answers seem equivalent. – twofeet Mar 13 '12 at 8:52

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.

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accepted as a bug in amsart, and one not previously found. i thought it might be possible to obscure the cause of the problem by hiding the comma in a box, but on further examination, that turns out not to be the case. – barbara beeton Mar 13 '12 at 18:03

This seems like a LaTeX bug not ams bug. Try

\documentclass{article}
\title{A Document}
\author{Author}
\begin{document}
\footnote{Test}
\makeatletter
\showthe\sf@size
\makeatother
$1+2=3$
\footnote{Test}
\end{document}


which gives

\sf@size ->6


but

\documentclass{article}
\title{A Document}
\author{Author}
\begin{document}
\footnote{Test}
$1+2=3$
\makeatletter
\showthe\sf@size
\makeatother
\footnote{Test}
\end{document}


gives

\sf@size ->7


That is before math mode, \sf@size=6 but after math mode \sf@size=7 (due to LaTeX redefining \sf@size i.e. \DeclareMathSizes{\@xpt}{\@xpt}{7}{5}).

Let's now look at the difference between \@makefnmark definition in LaTeX and ams. In file latex.ltx, \@makefnmark is defined as

\def\@makefnmark{\hbox{\@textsuperscript{\normalfont\@thefnmark}}}


That is you enter math mode and insert footnote number so the value of \sf@size for each footnote is 7.

but in ams classes, this is how \@makefnmark is defined as

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


That is footnote number is always, entered in horizontal mode (you never enter math mode). So if you are wondering what happens in

\documentclass{article}
\title{A Document}
\author{Author}
\begin{document}
\footnote{Test}
$1+2=3$
\makeatletter
\showthe\sf@size
\makeatother
\footnote{Test}
\end{document}


is that for the first footnote \sf@size=6 but once LaTeX sees the math mode, it changes \sf@size=7 so the next footnote number is typeset with \sf@size=7. In LaTeX, since you always typeset the footnote number in math mode, then \sf@size=7 for all footnotes but in ams classes, since footnote number is typeset in horizontal mode, the value of \sf@size changes from 6 to 7 once you typeset some mathematics.

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Welcome to TeX.SX! – Claudio Fiandrino Nov 11 '14 at 16:58