No, arc-transitivity is quite easy:
G.to_directed().line_graph().is_vertex_transitive()
Are you saying that the graph with 6 vertices and no edges is not a
graph? What about the graphs on 1,2,..5 vertices and no edges?
Because those are all counted in OEIS. Even on Mathworld, it says
"Counting e
On Monday, 29 October 2012 22:49:03 UTC+1, Tom wrote:
>
> Here's a list of 21 edge-transitive graphs on 6 vertices.
>
> "E???" # 6 K_1
> "E_??" # K_2 + 4
> "Eo??" # S_2 + 3
> "Ew??" # K_3 + 3
> "Es??" # S_3 + 2
> "Es_?" # S_4 + 1
> "Esa?" # S_5
> "E`??" # 2 K_2 + 2
> "Er??" # C_4 + 2
>
Here's a list of 21 edge-transitive graphs on 6 vertices.
"E???" # 6 K_1
"E_??" # K_2 + 4
"Eo??" # S_2 + 3
"Ew??" # K_3 + 3
"Es??" # S_3 + 2
"Es_?" # S_4 + 1
"Esa?" # S_5
"E`??" # 2 K_2 + 2
"Er??" # C_4 + 2
"E~??" # K_4 + 2
"Elg?" # K_{3,2} + 1
"Ehc?" # C_5 + 1
"E~{?" # K_5 + 1
"E`__" # 2 S_2
"Eli
This works yes. However it still leaves open what is going on with
disconnected graphs and what is the problem with the proposed
is_edge_transitive method!
Do you (or anyone) happens to see a bug or a bizarre mistake in the
implementation?
On Monday, 29 October 2012 20:02:40 UTC+1, Tom wrote
Sorry, I meant n=8.
sage: print [ec(n) for n in range(9)]
[1, 1, 1, 2, 3, 4, 6, 5, 8]
On Mon, Oct 29, 2012 at 11:41 AM, Tom Boothby wrote:
> Wanna run that on connected graphs? I get the correct sequence out to n=9 for
>
> def ec(n)
> c = 0
> for g in graphs(n):
> if g.is_connec
Wanna run that on connected graphs? I get the correct sequence out to n=9 for
def ec(n)
c = 0
for g in graphs(n):
if g.is_connected() and g.line_graph().is_vertex_transitive():
c+= 1
return c
On Mon, Oct 29, 2012 at 11:37 AM, Jernej Azarija wrote:
> Hello!
>
>
Hello!
Yes but this appears to be even more bogus. Consider this:
==
def ec(n):
c = 0
for el in graphs.nauty_geng(str(n)):
if (el.line_graph()).is_vertex_transitive():
c+=1
return c
==
sage: ec(7)
27
sage: ec(8)
39
But there are 26 and 40 edge-transitive graphs o
I use G.line_graph().is_vertex_transitive()
On Mon, Oct 29, 2012 at 7:12 AM, Jernej Azarija wrote:
> Hello!
>
> I am slowly implementing a patch that will provide some features for
> symmetry testing of graphs.
>
> However I am already puzzled by the following attempt at testing for
> edge-transi
