See examples in Sets.mw
FG_member(g,S,$)::nonnegint returns the order number of element g
in S or zero if S does not contain g.FG_in(SS,S,$)::boolean determine if SS is subset of S.FG_equal(S1,S2)::boolean evaluate if S1=S2.FG_set(preS,$)::S removes identical elements from preS.FG_prod(S1,S2,$)::preS returns the elementwise product of two sets.FG_transform(S,T,$)::S
transform each element of S by g->Ti*g*T.