How to define another proof environment, say, for the "Proof of lemma"? Also, how to make it without the qed box? (I need one with qed box, and another one without qed box.)
I'm using amsbook document class with amsthm package.
[Tex/LaTex] Custom proof environment
amsthmtheorems
Related Solutions
It is possible to "lift" the proof environment code from ntheorem:
\documentclass{article}
\usepackage[thmmarks]{ntheorem}% http://ctan.org/pkg/ntheorem
\makeatletter
\newcommand{\openbox}{\leavevmode
\hbox to.77778em{%
\hfil\vrule
\vbox to.675em{\hrule width.6em\vfil\hrule}%
\vrule\hfil}}
\gdef\proofSymbol{\openbox}
\newcommand{\proofname}{Proof.}
\newcounter{proof}\newcounter{currproofctr}\newcounter{endproofctr}%
\newenvironment{proof}[1][\proofname]{
\th@nonumberplain
\def\theorem@headerfont{\itshape}%
\normalfont
%\theoremsymbol{\ensuremath{_\blacksquare}}
\@thm{proof}{proof}{#1}}%
{\@endtheorem}
\makeatother
\theoremstyle{plain}
\theoremheaderfont{\normalfont\itshape}
\theorembodyfont{\normalfont}
\newtheorem*{myenv}{Note}
\begin{document}
\begin{myenv}
The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy dog.
\begin{proof}
This statement is true, because the fox did jump over the lazy dog.
\end{proof}
\end{myenv}
\end{document}
The QED-symbol is displayed when using the thmmarks package option of ntheorem. In ntheorem this is manually defined in \openbox, and subsequently used as \proofSymbol.
If you remove the blank line between This is the concluding line of the proof. and the \end{proof}, the problem disappears.
Best Answer
if you're using
amsthm, you don't need another proof environment. the features you want are already built in.to get a heading "Proof of lemma", use
to omit the box, just before
\end{proof}insert(this does not persist after the proof ends.)
both features are described in the manual:
texdoc amsthm