GeodesicsGraph( gamma, x, y )
This function returns the the graph induced on the set of geodesics between vertices x and y, but not including x or y. This function is only for a simple graph gamma.
gap> GeodesicsGraph( JohnsonGraph(4,2), 1, 6 ); rec( isGraph := true, order := 4, group := Group( (1,3)(2,4), (1,4)(2,3), (1,3,4,2) ), schreierVector := [ -1, 2, 1, 2 ], adjacencies := [ [ 2, 3 ] ], representatives := [ 1 ], isSimple := true, names := [ [ 1, 3 ], [ 1, 4 ], [ 2, 3 ], [ 2, 4 ] ] ) gap> GlobalParameters(last); [ [ 0, 0, 2 ], [ 1, 0, 1 ], [ 2, 0, 0 ] ]
GAP 3.4.4