Using "shaded" in thmtools and add space below and above

Question

In the following example

\documentclass{scrartcl}
\usepackage{blindtext}
%
\usepackage{amsthm}
\usepackage{thmtools}
%   
\declaretheoremstyle[%
    spaceabove=60pt, spacebelow=60pt, % just for testing
    shaded={rulecolor=black,rulewidth=.5pt,bgcolor={rgb}{1,1,1}}
]{framed}
\declaretheorem[style=framed]{theorem}
%
\begin{document}

\blindtext
%
\begin{theorem}
$ \int $ and some text
\end{theorem}
%
\blindtext
\end{document}

there will be no space added below and above. Without the shaded-declaration everything is fine. How can I achieve to add some space above and below?

You won't have these problems with ntheorem and the framed package. Further, shaded theorems will be able to break across pages, if necessary. — Bernard, May 19 '21 at 18:41
The problem with ntheorem is, that it's last release is from 2012 and sometimes it is not working as described, e.g. to use \ensuremath{_\blacksquare} in the proof-environment as described on page 9 of the manual is not working. One has to add the package wasysym (at least I had to do this). — Ulrich, May 20 '21 at 09:32
Personally, I never had any problem – which doesn't mean, of course, it can't have. But why don't you use, as an end-of-proof marker, \textsc{q.e.d.}, or even E.O.Δ. ? ;ο) — Bernard, May 20 '21 at 09:39

score 1 · Accepted Answer · answered May 19 '21 at 18:58

This seems to be an oversight in thmtools. The package defines shaded as adding \begin{shadebox} and \end{shadebox} around the theorem, but then the space settings are not taken into account.

You can redefine the shaded style by adding the settings explicitly. This also requires to load a few involved packages in your own preamble to make the necessary settings available during the definition.

MWE:

\documentclass{scrartcl}
\usepackage{blindtext}
%
\usepackage{amsthm}
\usepackage{thmtools}
\usepackage{shadethm}
\usepackage{thmdef-shaded}
%
\makeatletter
\define@key{thmdef}{shaded}[{}]{%
  \addtotheorempreheadhook[\thmt@envname]{%
      \setlength\shadedtextwidth{\linewidth}%
      \kvsetkeys{thmt@shade}{#1}\vspace{\thmt@style@spaceabove}\begin{shadebox}}%
    \addtotheorempostfoothook[\thmt@envname]{\end{shadebox}\vspace{\thmt@style@spacebelow}}%
  }
\makeatother
\declaretheoremstyle[%
    spaceabove=60pt, spacebelow=30pt, % just for testing
    shaded={rulecolor=black,rulewidth=.5pt,bgcolor={gray}{0.5}}
]{framed}
\declaretheorem[style=framed]{theorem}
%
\begin{document}

\blindtext
%
\begin{theorem}
$ \int $ and some text
\end{theorem}
%
\blindtext
\end{document}

Result:

score 0 · Answer 2 · answered May 20 '21 at 15:14

Comment: I found a solution using mdframed :

\declaretheoremstyle[mdframed={outerlinewidth=6pt,
                               innertopmargin=6pt, 
                               innerbottommargin=6pt} 
                    ]{mystyle} 
\declaretheorem[style=mystyle]{theorem}

But ntheorem should be the better solution because it "respects" page breaks.

Using "shaded" in thmtools and add space below and above

2 Answers2