http://mathforum.org/kb List of forum topics en http://mathforum.org/kb/thread.jspa?messageID=7893329&tstart=0#7893329 $J_{n,m}$ has as vertex set all subsets of $N$ of cardinality $m$, two]]> Sep 20, 2012 6:00:02 AM Sep 20, 2012 6:00:02 AM rcm@gmx.co.uk 0