\documentclass{amsart} \usepackage[all, ps, dvips]{xy} % Loading the XY-Pic package                                 % Using postscript driver for smoother                                 % curves \usepackage{color}              % For invisible frame \begin{document} \thispagestyle{empty} % No page numbers \SelectTips{eu}{}     % Euler arrowheads (tips) \setlength{\fboxsep}{0pt} % Frame box margin {\color{white}\framebox{{\color{black}$$ % Frame for margin  \xymatrix{    \mathrm{SZ}(V)         \ar@{^(->}[r]                      \ar@{^(->}[d]  & \mathrm{Z}(V)\cong F^* \ar@{->>}[r]^(.6){\det \cong z^n}  \ar@{^(->}[d]  & (F^*)^n                                                   \ar@{^(->}[d] \\    \mathrm{SL}(V)         \ar@{^(->}[r]                  \ar@{->>}[d]  & \mathrm{GL}(V)         \ar@{->>}[r]^{\det}            \ar@{->>}[d]  & F^*                                                   \ar@{->>}[d] \\    \mathrm{PSL}(V)        \ar@{^(->}[r]  & \mathrm{PGL}(V)        \ar@{->>}[r]  & F^*/(F^*)^n }  $$}}} % end math, end frame \end{document}