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enumerate subgraphs with edge sets

asked 2014-01-28 00:32:09 +0100

nkothari gravatar image


I have been using Sage for the past few months now, and I use the subgraph_search_iterator() heavily. So far, I did not care for the edge set of the subgraph found. But now that I do, it seems that the subgraph_search_iterator() returns only the vertex sets of the corresponding subgraphs.

In particular, I am looking for subdivisions of K3,3 in an input graph. But I want the additional constraint that two fixed vertices (say, u and v) must be branch vertices of the subgraph found - by branch vertices I mean vertices of degree exactly 3 in the subgraph.

Any help would be greatly appreciated. Thanks!

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answered 2014-01-28 07:15:59 +0100

Nathann gravatar image

updated 2014-01-28 07:16:08 +0100

Hello !

When you call G.subgraph_search_iterator(H), the first vertex of the list is matched with H.vertices()[0], the second with H.vertices()[1], etc ... So you know how edges of H are mapped to edges of G

1- This should appear in the documentation of subgraph_search_iterator -- if it does not, that should be fixed

2- It would be better to ask questions on our sage-devel or sage-support google group. If you were to answer my comment I would have no way to know, while Google groups sends us emails in that case. That's way easier :-P

Have fuuuuuuuuuuuuuuuuuuuuuuuuuuun !


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@Nathann - I was almost worried your body had been snatched when you spelled "Hello" with only one "o"! Luckily you snatched it back by the end of your answer :)

kcrisman gravatar imagekcrisman ( 2014-01-28 13:39:16 +0100 )edit

@nkothari - regarding point 2, actually it is fine to ask questions here. But one does have to know that there aren't automatic email updates when comments are posted on this site.

kcrisman gravatar imagekcrisman ( 2014-01-28 13:40:19 +0100 )edit

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Asked: 2014-01-28 00:32:09 +0100

Seen: 206 times

Last updated: Jan 28 '14