# Problem with citation in \thanks using amsart and hyperref with pagebackref

I'm writing a paper using amsart and the pagebackref option of hyperref. I want to use the \thanks command to acknowledge someone for pointing me to a specific reference. But I get an error. Simplified code giving the error is:

\documentclass{amsart}
\usepackage[pagebackref]{hyperref}
\begin{document}
\title{Error}
\author{Michael E. Zieve}
\thanks{Thanks for pointing me to \cite{PS}.}
\maketitle

\section{Introduction}
blah

\begin{thebibliography}{9}

\bibitem{PS} foo

\end{thebibliography}

\end{document}


and the error is

! Undefined control sequence.
<write> ...{\backcite{PS}{{\thepage }{\@thefnmark
}{Doc-Start}}}
l.18 \end{document}


Any suggestions?

• \thanks footnotes in amsart are set without footnote markers. i've forgotten how the markers are suppressed, but that's the place to look. haven't time now to investigate, but will register it as something that should be looked at. but, under the circumstances, there really isn't anything to be linked back to. i'd suggest a brief acknowledgments section at the end of the article. – barbara beeton Oct 25 '14 at 21:21
• @Aradnix -- that doesn't work with amsart'. the handling of top matter is quite different in amsart than in article. – barbara beeton Oct 25 '14 at 21:23
• @barbarabeeton Ooops, that's right, I forgot that the class was amsart instead of article -_\ my fault. – Aradnix Oct 25 '14 at 21:25
• @barbara: thanks. If I understand correctly, the issue is that TeX doesn't know what page the reference inside the \thanks appeared on, due to the way \thanks is handled. Is there some good reason why it should be difficult to design a footnote command for TeX in which this page number is known? – Michael Zieve Oct 26 '14 at 15:07
• @MichaelZieve -- i've been trying to think how an anchor might be set in the footnote. there is probably some mechanism in hyperref that might be usable; but i'm not familiar enough with the details of hyperref to come up with it without a fair amount of research (i.e., digging in the manual). someone more familiar with hyperref might find it faster. i'd look for a way to "wrap" the \ref` as an anchor point and label that, so that what was being anchored would show up when using a back reference. obviously, absence of a footnote marker doesn't provide a usable anchor. – barbara beeton Oct 26 '14 at 15:24