\documentclass[12pt,a4paper]{article} \usepackage[utf8x]{vietnam} \usepackage{xypic} \begin{document} \[ \xymatrix { G \ar[r]^{Ad} & Aut\left( \mathcal{G} \right) \\ \mathcal{G} \ar[r]^{ad} \ar[u]^{exp_G} & End \left( \mathcal{G} \right) \ar[u]_{exp} } \] \end{document}