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Dear Michael Leithold,

I have gap 4.1 and I compute all extensions of G by a G-module M with

'Extensions'. Is there a function which returns the module M as a

subgroup of an extension F? Or at least returns M as a group?

I think there is currently only one method for `Extensions' in the

GAP 4 library and that is the method for a finite soluble group G.

For this case, I enclose below a function which returns the elementary

abelian normal subgroup of the extension F which corresponds to the

given module.

With the next GAP 4 release I will also add a similar method to the GAP

library.

Best wishes, Bettina Eick ## ## F is the extension of the finite soluble group G with a G-module M ## ModuleOfExtension := function( G, F ) local n, m; n := Length(Pcgs(G)); m := Length(Pcgs(F)); return Subgroup(F, Pcgs(F){[n+1..m]} ); end;

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