# Problem with cross-referencing subsections in Appendix

I have a problem with cross-referencing subsections in the appendix using the AER-AEA document class. Here is an example:

\documentclass[AER]{AEA}
\newtheorem{proposition}{Proposition}

\begin{document}

\begin{proposition}\label{Prop1}
Interesting proposition.
\end{proposition}

Proof of Proposition~\ref{Prop1} is in Appendix~\ref{appendix_A1}.\\

\appendix
\section{Appendix}
\subsection{Proof of Proposition~\ref{Prop1}}\label{appendix_A1}
Proof is here.

\end{document}


This code gives:

Proof of Proposition 1 is in Appendix A.A1.

But I would like to get:

Proof of Proposition 1 is in Appendix A1.

• Where is this AEA document class from? – user31729 Jul 19 '17 at 15:48
• More to the point, does it support chapters? Try printing \thechapter or \thesection or \thesubsection in the appendix. – John Kormylo Jul 19 '17 at 16:22
• It is the LaTeX style for The American Economic Review journal of the American Economic Association . (aeaweb.org) – Lednacek Jul 19 '17 at 16:46
• When I put \thesubsection after "Proof is here." I get "A1" on the pdf output. – Lednacek Jul 19 '17 at 16:48
• In the aux file you should find \newlabel{appendix_A1}{{A1}{1}} – John Kormylo Jul 20 '17 at 4:24

The AEA class

does

\renewcommand\thesubsection{\thesection\@arabic\c@subsection}


in the \appendix command, i.e. prepending with \thesection, which is \@Alph\c@section effectively.

The reference format \p@subsection can be changed to use \theproposition only, by removing specific code for subsection.

Please note that journal editors might reject this change.

Edit: Some explanations

The macro \g@addto@macro adds additional code to an existing macro code, so \g@addto@macro{\appendix}{foo} would lead to printing foo if \appendix has been used.

Since this \g@addto@macro is a macro with @ - letter in its name, the \makeatletter...\makeatother macro pair is needed to allow @ in macro names.

The \AtBeginDocument hook 'guarantees' that our local changes to \appendix are done at the beginning of the document, after all other \AtBeginDocument - hooks that are provided by the class or the packages, so our changes are the last in this chain of commands.

\documentclass[AER]{AEA}
\newtheorem{proposition}{Proposition}

\makeatletter
\AtBeginDocument{
}
\makeatother

\begin{document}

\begin{proposition}\label{Prop1}
Interesting proposition.
\end{proposition}

Proof of Proposition~\ref{Prop1} is in Appendix~\ref{appendix_A1}.\\

\appendix
\section{Appendix}
\subsection{Proof of Proposition~\ref{Prop1}}\label{appendix_A1}
Proof is here.

\end{document}


• Thanks so much! Completely solved my problem! Fingers crossed so that it goes through at the journal. Just for my own education, where could I find any material to help me understand what exactly this bit of code does? \makeatletter \AtBeginDocument{ \g@addto@macro{\appendix}{\renewcommand{\p@subsection}{}} } \makeatother so that next time I can do it myself? Many thanks again! – Lednacek Jul 20 '17 at 10:17
• @Lednacek: Added some explanation – user31729 Jul 20 '17 at 20:26
• Thank you SO much! This is very clear and extremely helpful! – Lednacek Jul 21 '17 at 16:07
• @Lednacek: Forgot to mention the source of such material: Well, reading the LaTeX core code in latex.ltx and the class files helps a lot, but of course, the learning curve is steep (it was and sometimes still is for me too). ... and you find some 'dirty' tricks here on TeX.SE of course as well ;-) – user31729 Jul 21 '17 at 16:14