Diego Rattagi asked:
I have a question about SimsName and IdGroup:gap> G1 := PrimitiveGroup(10,5);; gap> SimsName(G1); "M_10"
While you did not state the version of GAP you are using, I deduce from
this output that it is 4.1.
> What's the reason for this ?
Version 4.1 contains a couple of known bugs in the primitive groups
library. In the current release GAP4.2, the problem you observed is gone:
gap> G1 := PrimitiveGroup(10,5);; gap> SimsName(G1); "S(6)" gap> IdGroup(G1); [ 720, 763 ] gap> G2 := PrimitiveGroup(10,6);; gap> SimsName(G2); "M_10" gap> IdGroup(G2); [ 720, 765 ]
I would therefore strongly urge you to update to the recent version.
Best wishes and apologies for the confusion you encountered,