I'm using GAP (gap4r4p6-win.zip) to investigate some permutation groups. group1 := Group([ (1,3)(2,5)(4,7)(6,8), (1,4)(2,6)(3,7)(5,8), (1,5)(2,3)(4,8)(6,7), (2,3,4,5,7,8,6), (3,4,7)(5,6,8) ]); group2 := Group([ (1,3,4,7,2,6,8), (1,8,7,5,3,6,2) ]); group3 := SymmetricGroup([1..8]);
RepresentativeAction(group3,group1,group2); gives: Error, no method found! For debugging hints type ?Recovery from NoMethodFound Error, no 1st choice method found for `ONE' on 1 arguments called from OneOp( elm ) called from One( F ) called from CallFuncList( Refinements.(Rf.func), Concatenation( [ rbase, image ], Rf.args ) ) called from RRefine( rbase, image, false ) called from PBEnumerate( 1, not repr ) called from ... Entering break read-eval-print loop ... you can 'quit;' to quit to outer loop, or you can 'return;' to continue Is this expected? My work around is to use First(AsList(group3),e->group1^e=group2); If this gets too slow, then I might use IsomorphismGroups(group1, group2) to see first of all whether the groups are isomorphic or compare cycle structures of the elements. signature2:= function(g) local cg,c2; cg := ConjugacyClasses(g); c2 := List(cg, c->[CycleStructurePerm(Representative(c)),Size(c)]); return SortedList(c2); end; to weed out groups which are clearly not conjugate. [The reference manual for IsConjugate says 'This command is only a shortcut to RepresentativeOperation.' I presume this should be updated to the prefered name of RepresentativeAction.] Andrew Johnson _______________________________________________ Forum mailing list [email protected] http://mail.gap-system.org/mailman/listinfo/forum
