InducedSubgraph( gamma, V )
InducedSubgraph( gamma, V, G )
This function returns the subgraph of gamma induced on the vertex list V (which must not contain repeated elements). If the optional third parameter G is given, then it is assumed that G fixes V setwise, and is a group of automorphisms of the induced subgraph when restriced to V. This knowledge is then used to give an associated group to the induced subgraph. If no such G is given then the associated group is trivial.
gap> gamma := JohnsonGraph(4,2);; gap> S := [2,3,4,5];; gap> InducedSubgraph( gamma, S, Stabilizer(gamma.group,S,OnSets) ); rec( isGraph := true, order := 4, group := Group( (2,3), (1,2)(3,4) ), schreierVector := [ -1, 2, 1, 2 ], adjacencies := [ [ 2, 3 ] ], representatives := [ 1 ], isSimple := true, names := [ [ 1, 3 ], [ 1, 4 ], [ 2, 3 ], [ 2, 4 ] ] )
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