Defining running headers

Question

I'm formatting a paper for a journal that uses the style sheet rmj-public.cls. The formatted output includes a running title at the top of each page. The default text used for the running title is the title defined using the \title{} command. Unfortunately, the title is too long to fit, so I'd like to define a short title. rmj-public.cls seems to contain code for using a short title, but I don't know what code I have to use to define it.
The entire style sheet is available at https://rmmc.asu.edu/rmj/RMJstyle.html The lines of the style sheet that I think are important are

\def\@prepheadcontent{%
  \uppercasenonmath\shorttitle
  \ifx\@empty\shortauthors \let\shortauthors\shorttitle
  \else \andify\shortauthors \uppercasenonmath\shortauthors\fi 
  }

In this code, I don't understand the meaning of the @ sign, e.g. @prepheadcontent and @empty. I also don't understand how to define shorttitle and shortauthors.

Answer 1

The rmj-public class is based on amsart, which in turn defines the title with an optional argument to use for headers:

\title[<short title>]{<complete title>}

% !TeX TS-program = pdflatex
\documentclass{rmj-public}
\usepackage{kantlipsum}% ONLY dummy text
%{ package and environment declarations }
\title[A short title for headings]{An article with a title to long to fit An article with a title to long to fit  An article with a title to long to fit  An article with a title to long to fit}
\author{First Author}
\address{First Author Address, Country}
\email{firstauthor email Address}
\thanks{My thanks}
\author{Second Author}
\address{Second Author Address, Country}
\email{secondauthor email Address}
\thanks{More thanks }
\date{month,day,year}
\keywords{keyword}
\subjclass{general}
\begin{document}
    \begin{abstract}
    \kant[1]
    \end{abstract}
    \maketitle
\section{Introduction}

\kant[1-5]


\end{document}