Dear Sir I have written code to get autocenter of a group , that is collection of all those elements in G which are fixed by all automorphisms of G, like center of G as centeral elements are fixed by all inner automorphisms of G . I have got the output. But i m not getting the structure description of the subgroup. I am getting the message no method is installed. I also want to know the way to feed a group with generators and relation.
Autocenter:=function(G) local aut,auts,L; aut:=AutomorphismGroup(G); L:=Filtered(AsList(G),g->ForAll(AsList(aut), auts->Image(auts,g)=g)); return(L); end; function( G ) ... end Autocenter(CyclicGroup(4)); Error, no method found! For debugging hints type ?Recovery from NoMethodFound Error, no 1st choice method found for `AsList' on 2 arguments Autocenter(CyclicGroup(4)); [ <identity> of ..., f2 ] StructureDescription(Autocenter(CyclicGroup(4))); Error, no method found! For debugging hints type ?Recovery from NoMethodFound Error, no 1st choice method found for `StructureDescription' on 1 arguments IsSubgroup(CyclicGroup(4),Autocenter(CyclicGroup(4))); false ALTERNATIVE WAY IS image:=function(G,g) local L,aut,auts,i,j; aut:=AutomorphismGroup(G); L:=[]; for auts in aut do AddSet(L, Image(auts,g));od; return(L); end; function( G, g ) ... end autc:=function(G) local H; H:=Filtered(G, g->Size(image(G,g)=1)); return(H); end; function( G ) ... end autc(CyclicGroup(4)); Error, no method found! For debugging hints type ?Recovery from NoMethodFound Error, no 1st choice method found for `Size' on 1 arguments. PLEASE SOLVE MY PROBLEM. With regards Harsha __ _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
