How to construct the quotient of a graph by a group of automorphisms

asked 2022-11-14 22:22:54 +0100

I've looked in the documentation, and am having trouble finding an easy way to construct the quotient of a graph by a group of automorphisms.

Once I've constructed a graph G, is there a way to specify a subgroup of G.automorphism_group() and construct the quotient of G by that subgroup?

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answered 2022-11-16 00:18:28 +0100

Max Alekseyev

7258 ●10 ●61 ●177

Something like this should do the job:

def MyFactor(G):
    A = G.automorphism_group()
    Orb = A.orbits()
    return Graph([list(Orb), [(o1,o2) for o1,o2 in Combinations(Orb,2) if any(G.has_edge(e1,e2) for e1 in o1 for e2 in o2)]])

MyFactor( graphs.FlowerSnark() ).show()

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Asked: 2022-11-14 22:22:54 +0100

Seen: 363 times

Last updated: Nov 16 '22

How to construct the quotient of a graph by a group of automorphisms edit

1 Answer