# How to draw diagrams of category theory? [duplicate]

Possible Duplicate:
How to draw a commutative diagram?

Some times when we want to describe diagrams in category theory such as $$\xymatrix{ U \ar@/_/[ddr]_y \ar@/^/[drr]^x \ar@{.>}[dr]|-{(x,y)} \\ & X \times_Z Y \ar[d]^q \ar[r]_p & X \ar[d]_f \\ & Y \ar[r]^g & Z }$$, we are used to use xypic package. However, it is not available now. So is there another way to draw diagrams?