categories: Final version of diagxy

[Michael Barr <barr@barrs.org>]

The final version is available as a diagxy.zip from 
ftp.math.mcgill.ca
by anonymous ftp in pub/barr/.  This includes the diagxy.tex and
diaxydoc.tex.  The former differs from the third version only in trivial
ways (some extra \ignorespaces were added to try to prevent extraneous
spaces from causing problems).  The opening pages of the documentation
are different, but the examples are all the same.