Subtitle, abstract and multiple authors using Titling package

Question

Following the excellent advice in this thread, I learned how to get a subtitle below the main title, using the titling package. Unfortunately, the trick runs into an error when you try including an abstract. Here's a minimal working example:

\documentclass[11pt]{amsart}
\usepackage{fullpage}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{amssymb}
\usepackage{amsfonts,mathrsfs}
\usepackage{amsxtra}

\usepackage{titling}
\newcommand{\subtitle}[1]{%
\posttitle{%
    \par\end{center}
\begin{center}\large#1\end{center}
\vskip0.5em}%
}

\begin{document}

\title{Title goes here}
\subtitle{Subtitle goes here}

\author{Author 1}
\address{Address 1}
\email{Email 1}

\author{Author 2}
\address{Address 2}
\email{Email 2}

\begin{abstract}
Abstract goes here
\end{abstract}

\maketitle

\section{Introduction}
Begin section 1...

\end{document}

Although the code compiles, it reports the warning No \author given and the abstract fails to appear in the PDF.

I would like to have the title, subtitle, abstract, and introduction to all appear on the 1st page. (I don't want a separate "title page", as the formatting needs to be compact for a limited-space journal article.) Thanks for your help!

Answer 1

The titling package is definitely incompatible with amsart.

You can easily implement a \subtitle command:

\documentclass[11pt]{amsart}

\makeatletter
\def\@settitle{\begin{center}%
  \baselineskip14\p@\relax
  \bfseries
  \uppercasenonmath\@title
  \@title
  \ifx\@subtitle\@empty\else
     \\[1ex]\uppercasenonmath\@subtitle
     \footnotesize\mdseries\@subtitle
  \fi
  \end{center}%
}
\def\subtitle#1{\gdef\@subtitle{#1}}
\def\@subtitle{}
\makeatother


\begin{document}

\title{Title goes here}
\subtitle{Subtitle goes here}

\author{Author 1}
\address{Address 1}
\email{Email 1}

\author{Author 2}
\address{Address 2}
\email{Email 2}

\begin{abstract}
Abstract goes here
\end{abstract}

\maketitle

\section{Introduction}
Begin section 1...

\end{document}

However, you get essentially the same effect by doing

\title{%
  Title goes here\\[1ex]
  \footnotesize\mdseries
  Subtitle goes here%
}
\shorttitle{Title goes here}

without tampering with the class.