# I want the QED symbol to be 1 line lower at the end of proof

Just as my title says, I would prefer to have my qed symbol to be 1 line lower than the last line of my proof. By default its on the same line and aligned to the right.

How can I achieve this?

EDIT: See below code for an example:

\documentclass[11pt,a4paper]{article}
\usepackage[margin=3cm]{geometry}
\usepackage[english]{babel}
\usepackage{amsmath, amsthm}
\begin{document}

\begin{proof}
Hello there good chap! I'll put in another line here just to be sure its clear what I mean.
\end{proof}

\end{document}

-

\usepackage{etoolbox}
\patchcmd{\endproof}
{\popQED}
{\par\popQED}
{}
{}


In this way we patch the proof environment (its end part \endproof) to issue a \par before printing the qed symbol.

Complete MWE:

\documentclass[11pt,a4paper]{article}
\usepackage[margin=3cm]{geometry}
\usepackage[english]{babel}
\usepackage{amsmath, amsthm}

\usepackage{etoolbox}
\patchcmd{\endproof}
{\popQED}
{\par\popQED}
{}
{}

\begin{document}

\begin{proof}
Hello there good chap! I'll put in another line here just to be sure its clear what I mean.
\end{proof}

\end{document}


Output:

-
Exactly what I was looking for, thank you! – BallzofFury Feb 13 '14 at 11:18
@BallzofFury You're welcome, happy to help. – karlkoeller Feb 13 '14 at 11:19
This way it can jump to the next page at a page break I'm afraid... maybe something like \relax\ifhmode\\\else\par\fi\popQED ? – yo' Feb 13 '14 at 11:19
@tohecz no, this doesn't work. Maybe \nopagebreak[4]\par\popQED is better – karlkoeller Feb 13 '14 at 11:27
@karlkoeller It was just a shot in the darkness. That one should work probably. Another option might be redefining \qedsymbol to occupy the whole line width. – yo' Feb 13 '14 at 11:28

Don't do it. In most cases the tombstone will hang from nowhere.

\documentclass[a4paper]{article}
\usepackage{amsthm}

% lower the symbol and make it zero width
\renewcommand{\qedsymbol}{\raisebox{-\baselineskip}{\llap{\openbox}}}

\begin{document}

\begin{proof}
This is a proof that this setting is \emph{really bad}
\end{proof}

\end{document}


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In case you have a proof which is less than 1 line, I understand what you mean. But I find this doesn't happen too often. – BallzofFury Feb 13 '14 at 13:46
@BallzofFury One line or more is the same thing. – egreg Feb 13 '14 at 14:04

It seems sufficient (not thoroughly tested) to issue a \par\nobreak before the "QED paragraph" is set:

\documentclass{article}
\usepackage{amsthm,amsmath,xpatch}
\newtheorem{theorem}{Theorem}

% \xpatchcmd{<cmd>}{<search>}{<replace>}{<success>}{<failure>}
\xpatchcmd{\qed}{\leavevmode}{\par\nobreak\leavevmode}{}{}

\begin{document}
\begin{proof}
$$f(x) = ax^2 + bx + c$$
\end{proof}

\begin{proof}
$$f(x) = ax^2 + bx + c$$
Some more text.
\end{proof}
\end{document}

-