\documentclass[12pt]{amsart}
\usepackage{amsmath,amssymb,amsthm}
% Feel free to add other packages, but only standard ones (CTAN).
% Do not modify any lengths.
% Do not remove any comments.
\setlength{\textheight}{9in}
\setlength{\textwidth}{6in}
\setlength{\topmargin}{0in}
\setlength{\oddsidemargin}{0.4cm}
\setlength{\evensidemargin}{0.4cm}
\renewcommand{\baselinestretch}{1.4}
%
\theoremstyle{plain}
\newtheorem{theorem}{Theorem}
\newtheorem{lemma}[theorem]{Lemma}
\newtheorem{corollary}[theorem]{Corollary}
\theoremstyle{definition}
\newtheorem{definition}[theorem]{Definition}
\newtheorem{example}[theorem]{Example}
\theoremstyle{remark}
\newtheorem{remark}[theorem]{Remark}
%
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% Put your definitions here. Do not remove comments.
%begindefs
%enddefs
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%
\begin{document}
\title{Put your title here}
\author{A. U. Thor}
\thanks{The first author is supported by ...}%
\address{Address of the first author}
\email{auth@univ.ersi.ty}
\author{C. O. Author}
\thanks{The second author is supported by ...}%
\address{Address of the second author}
\email{coauth@univ.ersi.ty}
\maketitle
We kindly ask you to spellcheck your abstract and to verify that it compiles.
\begin{theorem}
The abstract should not exceed one page.
\end{theorem}
\begin{thebibliography}{xx}
\bibitem{article}O'Author, C., Thor, A.U., \emph{Article}. Journal,
volume, number, year, pages.
\bibitem{book} Riter, W. Book title. Series. Publisher, year.
\end{thebibliography}
\end{document}