# how to write underneath max in formula latex

$$\max\limits_{{P^{\circ}_t(j)}} E_{t}\sum_{s=0}^{\infty}\zeta^s M_{t,t+s} \left[P^{\circ}_{t+s}(j)-\mathcal{MC}_{t+s}(j)\righ‌​t]Y_{t+s}(j)$$


I take it the main issue is the typesetting of the curly braces around the material immediately below "max". Just change

\max_{{P^{\circ}_t(j)}}


to

\max_{\{P^{\circ}_t(j)\}}


Remember that in order to typeset curly braces, you must type \{ and \}, not just { and }.

No need for the \limits directive, by the way.

To fully reproduce the equation shown in the screenshot, you also need to provide \mid t items in two of the subscripts.

\documentclass{article}
\begin{document}
$$\max_{\{P^{\circ}_t(j)\}} E_{t} \sum_{s=0}^{\infty} \zeta^s M_{t,t+s} \left[ P^{\circ}_{t+s\mid t}(j) - \mathcal{MC}_{t+s}(j) \right] Y_{t+s\mid t}(j)$$
\end{document}