\section and \subsection alternating in the header

Question

Right now, I'm trying to finalize the layout of my diploma thesis - unfortunately I cannot figure out how to achieve the heading I want. I'm using the amsart document class and try to achieve the following by using the fancyhdr package:

• On even pages I want for the header: on the left, pagenumber on the right
• On odd pages: pagenumber on the left, on the right

Here is the relevant LaTeX code:

\documentclass[twoside,12pt]{amsart}
\usepackage{amssymb,amsthm,array,arydshln}
\usepackage[toc,page]{appendix}
\usepackage{multicol}
\usepackage[usenames,dvipsnames]{xcolor}
\usepackage{tikz}
\usepackage{graphicx}
\usepackage{hyperref}
\usepackage{fancyhdr}
\usepackage{geometry}
\geometry{a4paper}

\begin{document}
  \pagestyle{fancyplain}
  \fancyhf{}
  \lhead[\thepage]{\leftmark}
  \rhead[\leftmark]{\thepage}
  \title{test}
  \maketitle
\end{document}

I achieved two different outputs, depending on what I put in

\lhead[\thepage]{\leftmark}
\rhead[\leftmark]{\thepage}

\leftmark as well as \rightmark will display the title instead of the title of the (sub)section; and so far, using anything else results in the display of nothing

I read quite a few articles, but I am still totally lost, because none of them was written for my usage case, i.e. the amsart document class

I appreciate any help and will provide further information if needed

Answer 1

I removed all the unnecessary packages for the task at hand; just use the settings for fancyhdr in your document after setting the page geometry.

Remember also that hyperref should be loaded last, with your choice of packages (very few packages should be loaded after hyperref).

One has to patch the \@sect command provided by amsart, because this command does not issue the needed marks.

\documentclass[twoside,12pt]{amsart}
\usepackage{geometry}
\geometry{a4paper,headheight=12pt}

\usepackage{fancyhdr}
\pagestyle{fancy} % choose the "fancy" pagestyle
\fancyhf{}        % clear all headers and footers
% Now set the headers
\fancyhead[LE,RO]{\footnotesize\thepage}
\fancyhead[LO,RE]{\footnotesize\leftmark}

%%% This code should go after hyperref, if loaded
\usepackage{xpatch}
\makeatletter
\xapptocmd{\@sect}{\csname #1mark\endcsname{#7}}{}{}
\makeatother   

\usepackage{kantlipsum} % just for adding mock text

\begin{document}

\title{test}
\maketitle

\section{Test section}
\subsection{Test subsection}
\kant[1-12]

\end{document}