# How can I enable Q.E.D. mark at the end of proof using “svmono.cls”?

Tomb stone (Q.E.D. mark) is not displayed at the end of a proof when I use "svmono.cls" for my dissertation. How can I enable it?

Here is the code example:

<\documentclass[12pt,sectrefs]{svmono}
\usepackage{makeidx}
\usepackage{graphicx}
\usepackage{multicol}
\usepackage[bottom]{footmisc}
\usepackage{amsmath}
\usepackage{lipsum}
\makeindex

\begin{document}
\frontmatter
\mainmatter

\begin{theorem}
\lipsum[1-2]
\end{theorem}
\begin{theorem}
nonses\\
nonsesnse\\
nonsesnse\\
nonsesnse\\
nonsesnse\\
%nonsesnse\\
\end{theorem}

\begin{proof}
here is the proof.
\end{proof}

\end{document}
• Because the proof environment in svmono is defined without the tombstone. – egreg May 12 '16 at 12:54

The proof environment provided by svmono does not include the automatic QED symbol. Instead it provides a clumsy method for manually adding a tombstone.

You can solve the issue by loading amsthm, so long as you continue to use svmono methods for defining new theorem-like environments.

\documentclass[12pt,sectrefs]{svmono}

\usepackage{amsmath}

\let\proof\relax\let\endproof\relax
\usepackage{amsthm}

\begin{document}