Dear GAP-Forum,
Bruce Coletti asked:
What is the GAP3.4.4 function that returns a list of the points moved by a
permutation?
J"urgen Ecker pointed out already that there is no such function in GAP344.
In GAP4 there is a function which does essentially this and I append
the (slightly modified for GAP3) code for it. It takes a list of
permutations and determines all points moved by its elements.
Best regards,
Alexander Hulpke
############################################################################# ## #F MovedPointsPerms( <gens> ) . . . . . . . . moved points of permutations ## MovedPointsPerms := function( gens ) local mov, gen, pnt; mov := [ ]; for gen in gens do if gen <> () then for pnt in [ SmallestMovedPointPerm( gen ) .. LargestMovedPointPerm( gen ) ] do if pnt ^ gen <> pnt then mov[ pnt ] := pnt; fi; od; fi; od; return Set( mov ); end;