Dear Forum,
``Anvita'' wrote: > I am suspecting that GAP's function for finding composition factors > of a MeatAxe module could be producing an incorrect answer in the > following example which counts the multiplicities of composition factors > of the regular module for A_5 over its splitting field GF(4). No, what is happening in the calculation is that you don't construct the regular action, but the conjugation action of A on itself. (The default action is `OnPoints' which corresponds to the ^ operator.) > > A:=AlternatingGroup(5); > G:=Action(A,A); If you use GG:=Action(A,A,OnRight); > gg:=GeneratorsOfGroup(GG); > reg:=List(gg,g->PermutationMat(g,60,GF(4))); > M:=GModuleByMats(reg,GF(4)); > com:=MTX.CollectedFactors(M);; > List(com,t->[MTX.Dimension(t[1]),t[2]]); you get dimensions [ [ 1, 12 ], [ 2, 8 ], [ 2, 8 ], [ 4, 4 ] ] which I believe agrees with what some other system calculates. Regards, Alexander Hulpke _______________________________________________ Forum mailing list Forum@mail.gap-system.org http://mail.gap-system.org/mailman/listinfo/forum
