\documentclass{amsart}

\begin{document}

%\title{very very very very very very very very very looooooooooooooooooooooooooong loooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooooong}
\title{short}

\author{Somebody Looooooooooooooooooong}
\date{}

\maketitle{}

\end{document}
