fontsformattingtheorems
How can I get universal in my new environment normalfont instead of italic (default)?
I thought it was something simple like
\newtheorem{exercise}{ \normalfont}[chapter] `
but doesn't work. I could not find something similar but I think it is something simple, even for me as a new user to LaTeX.
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.
I don't know the official way of doing it, but here is a hack that does the job which:
theoremtitlefont=\normalfont to get the correct font in the titlemdframed theorem to be MDtheorem, and\newenvironment called theorem which inserts the desired ( and ) to the theorem name before passing it on to the MDtheorem.\newenvironment called theorem* to provide the same functionality without the numbering.
theorem* the mdframe style theoremtitlefont=\normalfont, did not seem sufficient so had to add a manual \normalfont.\documentclass{article}
\usepackage{mdframed}
\mdfdefinestyle{myFramedTheoremStyle}{%
frametitlealignment=\raggedright,
linecolor=red,
linewidth=4pt,
innertopmargin=0pt,
innerbottommargin=10pt,
innerleftmargin=10pt,
innerrightmargin=10pt,
frametitleaboveskip=5pt,
skipbelow=0pt,
theoremtitlefont=\normalfont,
font=\itshape
}
\mdtheorem[style=myFramedTheoremStyle]{MDtheorem}{Theorem}
\newcommand*{\Title}{}
\newenvironment{theorem}[1][]{%
\ifstrempty{#1}{\begin{MDtheorem}}{\begin{MDtheorem}[(#1)]}%
}{%
\end{MDtheorem}%
}%
\newenvironment{theorem*}[1][]{%
% Required `\normalfont` in `MDtheorem*`, but not in the `MDtheorem` environment
\ifstrempty{#1}{\begin{MDtheorem*}}{\begin{MDtheorem*}[\normalfont(#1)]}%
}{%
\end{MDtheorem*}%
}%
\begin{document}
\begin{theorem}[Riemann]
Let $X$... Nulla egestas congue ullamcorper. Suspendisse id dictum est. Quisque ut urna lorem. Sed non aliquet sem, quis sollicitudin ante.
\end{theorem}
\begin{theorem}
Let $X$... Nulla egestas congue ullamcorper. Suspendisse id dictum est. Quisque ut urna lorem. Sed non aliquet sem, quis sollicitudin ante.
\end{theorem}
\begin{theorem*}[Riemann]
Let $X$... Nulla egestas congue ullamcorper. Suspendisse id dictum est. Quisque ut urna lorem. Sed non aliquet sem, quis sollicitudin ante.
\end{theorem*}
\begin{theorem*}
Let $X$... Nulla egestas congue ullamcorper. Suspendisse id dictum est. Quisque ut urna lorem. Sed non aliquet sem, quis sollicitudin ante.
\end{theorem*}
\end{document}
Best Answer
I prefer the key--value syntax of the thmtools package (which may use
amsthmorntheoremas backend).