You can do this just by patching in a few optional commands to the proof
environment itself.
\documentclass{article}
\usepackage{amsthm}
\newenvironment{proofoutline}
{\renewcommand\qedsymbol{}\proof[Proof outline]}
{\endproof}
\begin{document}
\begin{proofoutline}
This is not a proof.
\end{proofoutline}
\end{document}
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
\begin{proof}[Proof of lemma]
to omit the box, just before \end{proof}
insert
\renewcommand{\qedsymbol}{}
(this does not persist after the proof ends.)
both features are described in the manual: texdoc amsthm
Best Answer
The easiest way to get Proof: (boldface italic) is to say
The
\@addpunct
command will not add its argument if it's preceded by a punctuation mark, so no change to the definition of theproof
environment is necessary.Note: the italic shape is already selected, so it's only necessary to add
\bfseries
. No braces are needed, as the heading is typeset as the optional argument to\item
, which forms a group by itself.One can, alternatively, patch the environment's definition in order to change
\@addpunct{.}
into\@addpunct{:}
and to add\bfseries
. Patching the environment withetoolbox
is tricky, because the environment has an optional argument:With the
xpatch
package it's easier: