# Missing $inserted in block environment I tried to compile the following using the beamer class: \begin{block} $$T(\mathcal{P})=\mathbb{R}$$ and $$\mathrm{M}(\mathcal{P})=\mathbb{R}_{+}^{3}/ \mathrm{S}_3$$ \end{block}  If I complie the math stuff alone, it works just fine, but when I put them inside a block environment, it says missing$ inserted.

What should I do?

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It's not related with your question, but I think you should read Why is $…$ preferable to ? –  Ignasi Feb 8 '12 at 11:18

The block-environment needs a title:

\begin{block}{TITLE}
\end{block}


you can get rid of the title for example if you use a space:

\begin{block}{\ }
...
\end{block}


At least, this solved your problem on my slides

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Thanks! I totally forgot that. In fact puting {} did the job. –  yaa09d Feb 8 '12 at 8:16
... and so if you don't supply a title, it grabs the next token as one which, in this case, is \$, and this causes it to get very confused. Note that there is a difference between {\ } and {} since {\ } specifies a title which happens to be a space but {} says "There's no title" and beamer treats the two differently. –  Andrew Stacey Feb 8 '12 at 14:09
that ist true, the option with {\ } adds a little space above the content inside the block environment, which is kind of nice in my opinion –  Matz Feb 8 '12 at 14:16