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;