\documentclass[12pt]{article} \usepackage{amssymb,amsmath,amscd,concmath,amsfonts} \usepackage{color} \pagestyle{empty} \begin{document} \begin{equation*} \Omega_o = \{L_r(0) r^{-m} e^{-i\theta}: -\frac{\pi}{2} \leq \theta \leq \frac{\pi}{2}\}. \end{equation*} \end{document}