Dear Forum,
consider
G:=TransitiveGroup(20,543);
The following commands show that G is an extension of A5xA5 with C4xC2:
N:=First(NormalSubgroups(G),n->Size(n)=60^2);;
StructureDescription(N);
StructureDescription(G/N);
Since A5xA5 is perfect and centerless, G can be constructed via
ExtensionsByGroupNoCentre from the grpconst package (according to the
manual):
K:=Group((1,2,3),(3,4,5),(6,7,8),(8,9,10));;
H:=Group((1,2,3,4),(5,6));;
LoadPackage("grpconst");
ext:=ExtensionsByGroupNoCentre(K,H);;
However, G does not appear in the list of extensions:
List(ext,x->IsomorphismGroups(x,G));
[ fail, fail, fail, fail, fail, fail, fail, fail, fail, fail, fail, fail ]
Any thoughts? I'm using GAP 4.7.8.
Best wishes,
Benjamin
_______________________________________________
Forum mailing list
Forum@mail.gap-system.org
http://mail.gap-system.org/mailman/listinfo/forum
