Nah, I'll pick up some review credit. On Sun, Nov 18, 2012 at 10:16 PM, Jernej Azarija <azi.std...@gmail.com> wrote: > 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> 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> >> > wrote: >> >> On 2012-10-30, Jernej Azarija <azi.s...@gmail.com> 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. > >
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