% Thanks to PDF2SVG, I can transform a PDF into SVG.
% Author: Ika
% Date: 11/04/2014

\documentclass{amsart}
\usepackage[paperwidth=8cm, paperheight=5cm, top=0cm, left=0cm, right=0cm, bottom=0cm]{geometry}
\usepackage{amsmath,amssymb,nopageno}
\usepackage[all]{xy}
\begin{document}
\Huge
\begin{equation*}
	\xymatrix@C+2em@R+2em{
	\pi^{-1}(U) \ar_{\pi}[d] \ar^{\varphi}[r] & U\times F \ar^{\mathrm{proj_1}}[dl]\\
	U
	}
\end{equation*}
\end{document}