Math & Science ⇒ amsthm: How to put a horizontal rule after theorem env.

[bugmenot2]

Hi,

I'm using amsthm for typesetting theorems. Now I want to put a horizontal rule below "theorem"-Environments. I know how to place rules, what I don't know is how to tell amsthm to write something below each theorem-Environment. The \newtheoremstyle command isn't of any help here, since it does not provide a parameter for that.

So far I have thought of two solutions:

The first is redefining the theorem environment to something like

Code: Select all

\renewenvironment{theorem}[1]{\begin{old_theorem}[#1]}{\end{old_theorem}\rule..}

But I don't know how to reference the old definition of theorem within my new definition. (One would have to rename the old environment before defining the new one, I guess, but I don't know how to archive this)

My other idea was to search amsthm.sty for the code that produces the end-of-theorem code, which I guess is

Code: Select all

\def\@endtheorem{\endtrivlist\@endpefalse }

and replace it with my own version. (Preferably without having to copy amsthm.sty and change it in-place.) But I don't know how to do this either.

[gmedina]

Hi,

the following example could give you some ideas:

Code: Select all

\documentclass{article}
\usepackage{amsthm}

\newtheorem{mytheo}{Theorem}

\newenvironment{theo}
  {\begin{mytheo}}
  {\par\noindent\hrulefill\end{mytheo}}

\begin{document}

\begin{theo}
text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text text
\end{theo}

\end{document}

[bugmenot2]

Quite simple. Thank you!

Edit: Ok. Figured out what went wrong in my approaches: My first one would have worked had I used \def and \let:

Code: Select all

\let\oldendtheorem\endtheorem
\def\endtheorem{MyStuff. \oldendtheorem}

My second one needs \makeatletter:

Code: Select all

\makeatletter
\def\@endtheorem{\hfill\rule{3ex}{0.3mm}\endtrivlist@endpefalse}
\makeatother