from
The Free On-line Dictionary of Computing (8 July 2008)
Xy-pic
<graphics, publication> A package for {typesetting} graphs and
diagrams using {TeX}. It is structured as several modules,
each defining a custom notation for a particular kind of
graphical object or structure. Example objects are arrows,
curves, and frames. These can be organised in matrix,
{directed graph}, path, polygon, knot, and 2-cell structure.
Xy-pic works with {LaTeX}, {AMS-LaTeX}, {AMS-TeX}, and {plain
TeX}, and has been used to typeset complicated diagrams from
many application areas including {category theory}, {automata}
theory, {algebra}, {neural networks} and {database} theory.
(http://ens-lyon.fr/~krisrose/Xy-pic.html).
(1997-11-20)