\documentclass[12pt]{amsart}

\theoremstyle{plain}
\newtheorem{theorem}{Theorem}[section]

\begin{document}

\author{Nikolai Ivanovich Lobachevsky}
\address{Kazan Federal University, Kazan, Tatarstan, Russia}
\email{nil@math.kpfu.ru}

\title[Obscurity]{On Fading Into Obscurity Despite Making A Very Important
Discovery}

\begin{abstract}
You would think I would have found fame and fortune after solving a problem
which was roughly 2000 years old.

But no, I was ignored and had to become a university administrator.
\end{abstract}

\keywords{sadness, bitterness, disappointment}

\thanks{We would like to thank C.F.Gauss and J.Bolyai for nothing!}

\date{\today}

\maketitle

\section{Introduction}\label{intro}

Hello ... world?

\section{Trying to go on}\label{trying}

And so I begin every day crying, as I did in \S\ref{intro}:
\begin{center}
Hello ... world?
\end{center}
but to no avail.

\section{Some mathematics}\label{math}

I do find solace in mathematics.  I (anachronistically) love the intricate
simplicity of equations like $e^{i\pi}+1=0$.  Sometimes I feel that equation
should be {\it displayed} on its own line, as
$$
e^{i\pi}+1=0
$$
although \LaTeX{} purists would probably encourage me to write it as
\begin{equation}\label{eulereqn}
e^{i\pi}+1=0
\end{equation}
or, if I never intended to refer to that equation by its number \eqref{eulereqn},
I might use
\begin{equation*}
e^{i\pi}+1=0 .
\end{equation*}

\section{Conclusion}

My life's great work:
\begin{theorem} The Parallel Postulate is independent of Euclid's other
postulates.
\end{theorem}

\end{document}