# troubleshoot needed for LaTeX Error: Command \item invalid in math mode [closed]

It gives me an

\item invalid in math mode

although I use a very similar casing on a previous frame.

\documentclass[mathserif]{beamer}
\usepackage{beamerthemesplit}
\usepackage{amsmath}
\usepackage{amsfonts}
\begin{document}
\begin{frame}[shrink=20]
Requiring the partition function to be modular invariant, gives some properties to $\epsilon(\alpha,\beta)$.
\begin{itemize}
\item Under $\tau \rightarrow \tau+1$
$$\{\alpha,\beta\} \rightarrow e^{-i\pi n(\alpha)/8}\{\alpha,\bar \alpha \beta\}.$$
This will require $\epsilon(\alpha,\beta)=\varepsilon_\alpha\epsilon(\alpha,\bar \alpha \beta\)$.
\item Under $\tau \rightarrow -\frac{1}{\tau}$
$$\{\alpha,\beta\} \rightarrow e^{i\pi n(\alpha \cap \beta)/4}\{\beta, \alpha\}.$$
This will require $\epsilon(\alpha,\beta)=\delta_\alpha\delta_\beta\epsilon(\beta, \alpha)\varepsilon_{\alpha \cap \beta}^{-2}$.
\end{itemize}
In the equations above $\varepsilon_\alpha=e^{-i\pi n(\alpha)/8}$.
\end{frame}
\end{document}

-

## closed as off-topic by egreg, Werner, Peter Grill, Alan Munn, Svend TveskægFeb 15 '14 at 23:52

• This question does not fall within the scope of TeX, LaTeX or related typesetting systems as defined in the help center.
If this question can be reworded to fit the rules in the help center, please edit the question.

Is this Beamer? –  Charles Staats Feb 15 '14 at 23:27
Welcome to TeX.SX! Please make your code compilable (if possible), or at least complete it with \documentclass{...}, the required \usepackage's, \begin{document}, and \end{document}. That may seem tedious to you, but think of the extra work it represents for TeX.SX users willing to give you a hand. Help them help you: remove that one hurdle between you and a solution to your problem. –  Adam Liter Feb 15 '14 at 23:31
You have \beta\)$ that should be \beta)$. –  egreg Feb 15 '14 at 23:32
Also, a tip: use $ ... $ instead of $$ ... $$. See Why is $…$ preferable to $$…$$?. –  Adam Liter Feb 15 '14 at 23:33
This question appears to be off-topic because it is about a simple typing error –  egreg Feb 15 '14 at 23:33

You have a spurious \) before the start of the second \item, which should only be ).