[GAP Forum] homomorphism construction wanted

[Hulpke,Alexander]

Dear Graham, Dear Forum,

> Is there a way to construct a group homomorphism using a variant of the function
> 
> f:=GroupHomomorphismByFunction(G,H,x->function(x))
> 
> for which
> 
> ImageElm(f,x)
> 
> does not test to see if x lies in G?  Here function(x) is a well-defined function for x in G, but G is a group for which I don't have a membership test.

In such situations (e.g. with matrix groups, using the `matgrp` package), I use `ImagesRepresentative` in place of `Image` or `ImageElm` to avoid membership test.

All the best,

   Alexander