[Nauty] Hard Graphs

[Gordon Royle]

Tough isomorphism problems for nauty arise from geometric graphs,
particularly the bipartite graph of a projective plane.

A good place to start is the list of planes of order 16 - these have 273
points and lines, and can be found at the URL

http://www.csse.uwa.edu.au/~gordon/remote/planes16/index.html

They are listed just as a collection of blocks, so you will need to turn
them into the bipartite graph before you use them.

You could either take them in pairs, and try to show that they are not
isomorphic, or simply randomly relabel one of them and try to show that
the two labellings *are* isomorphic.

Good luck.

-- 
Dr. Gordon F Royle, http://www.csse.uwa.edu.au/~gordon,
gordon at csse.uwa.edu.au
--