[GAP Forum] automorphisms and stabilizers

[Ryan Higginbottom]

Dear GAP folks:

Any help you can give me on this question would be appreciated.  I'm
fairly new to using GAP, so the answer might be simple, but I've searched
a bit on the GAP site without finding an immediate answer.  Forgive me if
this is trivial.

The automorphism group of a group G acts on the set S of subgroups of G. 
Given a particular subgroup V of G, I would like to compute the size of
Aut(G)_V, that is, the stabilizer in Aut(G) of V.  

I cannot figure out how to establish the proper action in this situation. 
I think that I will need something like the ExternalSet command, because
this doesn't look like a commonly used action (based on what I've seen in
the manual).  This seems like an easy computation though.  Can anyone
help?

Thank you.

Ryan Higginbottom


		
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