[GAP Forum] About Normalizer

[Dung Duong]

Dear GAP Forum,

I am totally new with GAP and I have a problem as below :

I have a group G:=AutomorphismGroup(PSL(2,9)). One of its Maximal subgroup
is $M =N_G(D_8)$. And I would like to computthe order of this group. So I
did as follows :

> G:=AutomorphismGroup(PSL(2,9));
> H:=DihedralGroup(8);
> Normalizer(G,H);

But it does not work. I think that somehow I need to "embed" H as a subgroup
of G. But I dont know how.

Please tell me how I can do.

Thanks in advance.

Best regards,

Dung Duong