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Statistic identifier: St001060
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Collection: Graphs
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Description: The distinguishing index of a graph.
This is the smallest number of colours such that there is a colouring of the edges which is not preserved by any automorphism.
If the graph has a connected component which is a single edge, or at least two isolated vertices, this statistic is undefined.
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References: [1] Kalinowski, Rafał, Pilśniak, M. Distinguishing graphs by edge-colourings [[MathSciNet:3286626]]
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Code:
def statistic(G):
"""the smallest number of colours such that there is a colouring of
the edges which is not preserved by any automorphism.
sage: [statistic(graphs.CycleGraph(r)) for r in range(3,7)]
[3, 3, 3, 2]
sage: [statistic(graphs.CompleteGraph(r)) for r in range(3,8)]
[3, 3, 3, 2, 2]
sage: [statistic(graphs.CompleteBipartiteGraph(1,r)) for r in range(3,8)]
[3, 4, 5, 6, 7]
"""
G = G.copy(immutable=False)
for c in range(G.num_edges()+1):
# try to find a colouring
V = G.edges(labels=False)
# partition the set of edges into c parts
for colouring in SetPartitions(V, c):
for i, block in enumerate(colouring):
for u, v in block:
G.set_edge_label(u,v,i)
if G.automorphism_group(edge_labels=True, order=True)[1] == 1:
return c
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Statistic values:
([(0,2),(1,2)],3) => 2
([(0,1),(0,2),(1,2)],3) => 3
([(1,3),(2,3)],4) => 2
([(0,3),(1,3),(2,3)],4) => 3
([(0,3),(1,2),(2,3)],4) => 2
([(1,2),(1,3),(2,3)],4) => 3
([(0,3),(1,2),(1,3),(2,3)],4) => 2
([(0,2),(0,3),(1,2),(1,3)],4) => 3
([(0,2),(0,3),(1,2),(1,3),(2,3)],4) => 2
([(0,1),(0,2),(0,3),(1,2),(1,3),(2,3)],4) => 3
([(1,4),(2,4),(3,4)],5) => 3
([(0,4),(1,4),(2,4),(3,4)],5) => 4
([(1,4),(2,3),(3,4)],5) => 2
([(0,4),(1,4),(2,3),(3,4)],5) => 2
([(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,4),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(1,3),(1,4),(2,3),(2,4)],5) => 3
([(0,4),(1,2),(1,3),(2,4),(3,4)],5) => 2
([(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,4),(1,3),(2,3),(2,4),(3,4)],5) => 2
([(0,4),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,3),(0,4),(1,3),(1,4),(2,3),(2,4)],5) => 2
([(0,3),(0,4),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,4),(1,3),(2,3),(2,4)],5) => 2
([(0,3),(1,2),(1,4),(2,4),(3,4)],5) => 2
([(0,3),(0,4),(1,2),(1,4),(2,4),(3,4)],5) => 2
([(0,3),(0,4),(1,2),(1,4),(2,3)],5) => 3
([(0,1),(0,4),(1,3),(2,3),(2,4),(3,4)],5) => 2
([(0,3),(0,4),(1,2),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,4),(1,2),(1,3),(2,3),(2,4),(3,4)],5) => 2
([(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 3
([(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4)],5) => 2
([(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,4),(3,4)],5) => 2
([(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 2
([(0,1),(0,2),(0,3),(0,4),(1,2),(1,3),(1,4),(2,3),(2,4),(3,4)],5) => 3
([(1,5),(2,5),(3,5),(4,5)],6) => 4
([(0,5),(1,5),(2,5),(3,5),(4,5)],6) => 5
([(1,5),(2,5),(3,4),(4,5)],6) => 2
([(0,5),(1,5),(2,5),(3,4),(4,5)],6) => 3
([(1,5),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,5),(2,5),(3,4),(3,5),(4,5)],6) => 3
([(0,5),(1,5),(2,4),(3,4)],6) => 3
([(1,5),(2,3),(2,4),(3,5),(4,5)],6) => 2
([(0,5),(1,5),(2,3),(3,4),(4,5)],6) => 2
([(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,5),(2,4),(3,4),(4,5)],6) => 3
([(0,5),(1,5),(2,3),(2,4),(3,5),(4,5)],6) => 2
([(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,5),(1,4),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 3
([(0,4),(0,5),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3
([(1,5),(2,4),(3,4),(3,5)],6) => 2
([(0,5),(1,4),(2,3),(3,5),(4,5)],6) => 2
([(1,4),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(0,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(1,4),(1,5),(2,3),(2,5),(3,4)],6) => 3
([(0,5),(1,4),(2,3),(2,4),(3,5),(4,5)],6) => 2
([(1,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,2),(1,4),(2,3),(3,5),(4,5)],6) => 2
([(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(2,3),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 1
([(0,5),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1
([(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(2,3),(2,4),(3,5)],6) => 2
([(0,5),(1,5),(2,3),(2,4),(3,4)],6) => 3
([(0,4),(1,2),(1,3),(2,5),(3,5),(4,5)],6) => 2
([(0,4),(1,2),(1,5),(2,5),(3,4),(3,5)],6) => 2
([(0,4),(1,2),(2,5),(3,4),(3,5),(4,5)],6) => 1
([(0,4),(1,4),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(0,3),(0,4),(1,2),(1,5),(2,5),(3,5),(4,5)],6) => 2
([(0,3),(1,4),(1,5),(2,4),(2,5),(3,5),(4,5)],6) => 2
([(0,4),(1,2),(1,5),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,5),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,5),(1,4),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,3),(0,5),(1,3),(1,5),(2,4),(2,5),(3,4),(4,5)],6) => 2
([(0,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 1
([(0,1),(0,5),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,4),(1,5),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,4),(0,5),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,3),(1,4),(2,3),(2,4),(3,5),(4,5)],6) => 2
([(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,5),(1,3),(1,4),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2
([(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2
([(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(2,5),(3,4)],6) => 2
([(0,3),(0,5),(1,2),(1,5),(2,4),(3,4),(4,5)],6) => 2
([(0,5),(1,2),(1,4),(2,3),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,2),(1,5),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,5),(1,3),(1,4),(2,4),(2,5),(3,4),(3,5)],6) => 1
([(0,1),(0,5),(1,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 1
([(0,4),(1,3),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 1
([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,5),(4,5)],6) => 2
([(0,5),(1,2),(1,3),(1,4),(2,3),(2,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,2),(1,3),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,3),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,4),(2,3),(2,5),(3,4),(3,5),(4,5)],6) => 1
([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(2,3),(4,5)],6) => 4
([(0,2),(1,4),(1,5),(2,3),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,5),(1,5),(2,3),(2,4),(3,4),(4,5)],6) => 2
([(0,1),(0,5),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,5),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(2,3),(2,5),(3,4),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(1,4),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(0,3),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,3),(0,5),(1,2),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,3),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4)],6) => 2
([(0,1),(0,5),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,3),(0,4),(1,2),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,5),(3,5),(4,5)],6) => 2
([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,5),(3,4)],6) => 2
([(0,1),(0,3),(0,5),(1,2),(1,4),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,4),(0,5),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,2),(0,5),(1,3),(1,4),(1,5),(2,3),(2,4),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,5),(1,2),(1,3),(1,4),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 3
([(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,3),(0,4),(0,5),(1,2),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5)],6) => 2
([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
([(0,1),(0,2),(0,3),(0,4),(0,5),(1,2),(1,3),(1,4),(1,5),(2,3),(2,4),(2,5),(3,4),(3,5),(4,5)],6) => 2
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Created: Dec 12, 2017 at 11:00 by Martin Rubey
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Last Updated: Nov 18, 2021 at 11:51 by Martin Rubey