# You can't use \eqno' in math mode,Missing } inserted

I understand from previous post that this error come when you have extra {,( involved. But in my case i am not able to find any such case.

$$\overset{\wedge}{\pi}\left(\beta/ A_n\right) = \sum_{\alpha\epsilonA_n}\frac{n_\alpha}{n}\int exp(-t){F_{\alpha_1\beta_1}^\left(\theta,t,n\right)}.....{F_{\alpha_L\beta_L}^\left(\theta,t,n\right)}dt$$


Can anybody point me out the error? is wrong with this? . I am getting 6 errors in this i.e.

Undefined control sequence. \sum_{\alpha\epsilonA
Missing { inserted. exp(-t){F_{\alpha_1\beta_1}^\left
Missing { inserted. ...ight)}.........{F_{\alpha_L\beta_L}^\left
You can't use \eqno' in math mode.
Missing } inserted.
Missing } inserted.


You have some typing errors like \sum_{\alpha\epsilonA_n} and misplaced curly braces ... try the following:

\documentclass[border=3mm,preview]{standalone}
\usepackage{mathtools}

\begin{document}
$$\overset{\wedge}{\pi} \left(\beta/ A_n\right) = \sum_{\alpha\epsilon A_n}\frac{n_\alpha}{n} \int\exp(-t) F_{\alpha_1\beta_1}^{\left(\theta,t,n\right)} \dots F_{\alpha_L\beta_L}^{\left(\theta,t,n\right)}dt$$
Compare:
$\hat{\pi}\quad\widehat{\pi}\quad\overset{\wedge}{\pi}$

\end{document}


Also see, if the \hat{\pi} or \widehat{\pi} is more situated than \overset{\wedge}{\pi}.