On Oct 10, 2013, at 10/10/13 1:44, Sopsku <rrbu...@cox.net> wrote:
> > Sorry for being so dense, but I do not fully understand the command and it Indeed, it should have been (swapped indices 1,2) PreImagesRepresentative(Embedding(s,2), r/Image(Embedding(s,1),Image(Projection(s),r)); > fails so I am not quite sure what Prof. Hulpke intended. I did try the > following: Assuming your setup is: gap> g:=Group((1,2,3,4,5)); Group([ (1,2,3,4,5) ]) gap> a:=AutomorphismGroup(g); <group with 1 generators> gap> s:=SemidirectProduct(a,g); <pc group with 3 generators> gap> p:=Projection(s); [ f1, f2, f3 ] -> [ [ (1,2,3,4,5) ] -> [ (1,3,5,2,4) ], [ (1,2,3,4,5) ] -> [ (1,5,4,3,2) ], IdentityMapping( Group([ (1,2,3,4, 5) ]) ) ] gap> e1:=Embedding(s,1); CompositionMapping( [ f1, f2 ] -> [ f1, f2 ], CompositionMapping( Pcgs( [ (1,2,4,3), (1,4)(2,3) ]) -> [ f1, f2 ], <action isomorphism> ) ) gap> e2:=Embedding(s,2); [ (1,2,3,4,5) ] -> [ f3 ] > npart1:=function(elm) > return Image(e1,Image(p,elm))^p; > end; > > npart2:=function(elm) > return PreImagesRepresentative(e2,elm/Image(e1,Image(p,elm))); > end; > > PrintArray(List(Elements(S),e->[npart1(e),npart2(e)])); > > Which is more or less what I think I am looking for. Is this kind of what > Prof. Hulpke intended. Yes, though your function npart1 does nothing else but just computing Image(p,elm) Best, Alexander Hulpke > > Again thank you for any help or comments. > Ron > > > > > > > _______________________________________________ > Forum mailing list > Forum@mail.gap-system.org > http://mail.gap-system.org/mailman/listinfo/forum _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
