# formulas in bold theorem titles in ntheorem package

I'm not quite sure if this counts as a bug or a feature but I have the following problem with the ntheorem package. The theorem title is bold face, which I like, but in math formulas setting some (or all) letters to bold may change the meaning of the mathematical quantities (vectors are bold, scalars are normal etc)

So my question: how can I avoid that the mathematical formulas in the title of the theorem are changed but the rest of the title is still set in bold?

As far as I can see the problem does not occur in the (obsolete) theorem package.

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this is, at the very least, a design flaw for the reason you mention. this problem does not occur in the amsthm package. (the [optional] part of the theorem header there isn't normally bold at all, which some non-ams people feel is a design flaw. but even if this is overcome by a \newtheoremstyle, the math still won't be bold.) –  barbara beeton Jun 28 '12 at 13:55

The boldmath is inserted by

\def\theorem@checkbold{\if b\expandafter\@car\f@series\@nil\boldmath\fi}


so it looks as if you could go

\makeatletter

\def\theorem@checkbold{}

\makeatother


to disable that feature

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thanks that does the job! –  Stefan Waldmann Jun 28 '12 at 14:09
@StefanWaldmann: If that does the job, you can accept the answer given by David. –  Count Zero Jun 28 '12 at 15:49