Tom, I have created a patch implementing the edge/arc transitive tests. I mentioned on the wiki page that the main idea of the test was suggested by you, but in case you want to claim any extra credit or something, here is the track ticket:
http://trac.sagemath.org/sage_trac/ticket/13721 On Tuesday, 30 October 2012 18:19:26 UTC+1, Dima Pasechnik wrote: > > On 2012-10-30, Tom Boothby <tomas....@gmail.com <javascript:>> wrote: > > Oops, didn't see your reply before I posted. Not counting the empty > > graph is very very strange. At the very least OEIS needs to be > > updated to have a proper definition to warn people that the empty > > graph is excluded. > > it's a tricky question whether groups can be allowed to act on the empty > set. > If they aren't, then the empty graphs must be excluded. > I prefer to think of transitive actions having one orbit, while > allowing empty sets needs a change here: 0 or 1 orbits... > Allowing actions on empty sets loses you the 1-1 correspondence between > the transitive actions and the actions on cosets of subgroups. > So there is a lot to be lost here. > > Dima > > > > > > > > > On Tue, Oct 30, 2012 at 4:23 AM, Dima Pasechnik > > <dim...@gmail.com<javascript:>> > wrote: > >> On 2012-10-30, Jernej Azarija <azi.s...@gmail.com <javascript:>> > wrote: > >>> ------=_Part_1698_7171753.1351582604933 > >>> Content-Type: text/plain; charset=ISO-8859-1 > >>> > >>> On Monday, 29 October 2012 22:49:03 UTC+1, Tom wrote: > >>>> > >>>> Here's a list of 21 edge-transitive graphs on 6 vertices. > >>>> > >> [...] > >>>> They've all got 6 vertices. They're all edge transitive. That means > >>>> Weisstein's list is wrong. > >> > >> no, not really. He just doesn't count empty graphs. Somewhere on > >> http://mathworld.wolfram.com/Edge-TransitiveGraph.html > >> you can read: > >> > >> "Counting empty graphs as edge-transitive, the numbers of > edge-transitive > >> graphs on , 2, ... nodes are 1, 2, 4, 8, 12, 21, 27, .... " > >> > >> So it's a misunderstand related to definitions used, rather than > >> a bug in someone's code, it seems. > >> > >> Dima > > -- You received this message because you are subscribed to the Google Groups "sage-devel" group. To post to this group, send email to sage-devel@googlegroups.com. To unsubscribe from this group, send email to sage-devel+unsubscr...@googlegroups.com. Visit this group at http://groups.google.com/group/sage-devel?hl=en.
