theoremprework Error with ntheorem

Question

I have defined

\theoremheaderfont{\normalfont\bfseries}
\theoremprework{\bigskip\hrule}
\theorempostwork{\hrule\bigskip}
\theorembodyfont{\slshape}
\newtheorem{definition}[satz]{Definition}

and now i am able to write something like

\begin{definition}fooBar\end{definition}

but i am getting a weird behavior with the prework of the theorem! LaTeX sets the top \hrule on one page and the rest of the definition on another page! See here what i mean. Althoug it is german you can see that the top hrule of definition 1.2.7 is on page 6 while the rest can be found on top of page 7 (pages have a header line in my layout!). Any idea how to move this hrule to the same page as the definition without using \newpage to have still a dynamic document?

But i do not understand how to fix this with my template. I have way too many theorem environments to fix them easily. — Christian Ivicevic, Aug 04 '11 at 13:29
Philippe's answer to the linked question involved redefining the theorem environment. Does this not work for you? If not could you explain why not? — Seamus, Aug 04 '11 at 13:34
My environment is called definition and with renewenvironment the layout is screwed. Furthermore i have problems with the counter which in fact does not exist! Seems like i have to use \clearpage or \newpage... — Christian Ivicevic, Aug 04 '11 at 13:55
As Phileppe's answer says, theorems are defined as lists and so there are break points in them. I'm not sure there's much more help we can offer without more of a complete example and more explanation about why the solution in that other question isn't satisfactory. — Seamus, Aug 04 '11 at 14:01

score 2 · Accepted Answer · answered Aug 04 '11 at 15:31

I think the needspace pacakge might help here. Have a look at the code below

\documentclass{article}
\usepackage[standard,framed]{ntheorem}
\usepackage{needspace}
\theoremheaderfont{\normalfont\bfseries}
\theoremprework{\bigskip\needspace{\baselineskip}\hrule} % note this line
\theorempostwork{\hrule\needspace{\baselineskip}\bigskip} % note this line
\theorembodyfont{\slshape}
\newtheorem{mydefinition}{Definition}

\usepackage{lipsum}

\begin{document}

\begin{mydefinition}
\lipsum[1]
\end{mydefinition}

\end{document}

score 1 · Answer 2 · answered Oct 26 '11 at 22:55

You can also consider using mdframed:

\usepackage{ntheorem}
\usepackage[ntheorem]{mdframed}
\theoremheaderfont{\normalfont\bfseries}
\theorembodyfont{\slshape}
\newmdtheoremenv[
  innerleftmargin=0pt,innerrightmargin=0pt,
  topline,bottomline,leftline=false,rightline=false,
  skipabove=\bigskipamount,skipbelow=\bigskipamount,
  %innertopmargin=\topsep,
  innerbottommargin=\topsep
  ]{definition}[satz]{Definition}

theoremprework Error with ntheorem

2 Answers2

Linked