Let $G$ be a group and $H$ a subgroup. Suppose $M$ is a $kN\_G(H)$-module ($k$ a field). Then the $H$-fixed points in $M$ denoted $M^H$ is a $kN\_G(H)$-module. Is there a way to access this module in Magma?


More specifically, it is easy enough to find $M^H$ by calling Fix(Restriction(M,H)). But is there any way to force Magma to consider this as a $kN\_G(H)$-module, it only recognizes it as an $kH$-module.



Using Magma to Find a Fixed Points Module
This question is not about research level mathematics, so it is really not suitable for mathoverflow. But I'll answer it anyway. The code below works.



```
> G := Sym(6);         
> H := sub< G | (1,2,3) >;
> N := Normalizer(G,H);
> M := PermutationModule(G, GF(7));
> MH := Restriction(M,H);
> MN := Restriction(M,N);
> FMH := Fix(MH);
> m := Morphism(FMH,MH);                             
> S := sub< MN |  [ m(FMH.i) : i in [1..Ngens(FMH)]] >;

```

