Let rVabelemJmx v x : x \in G -> rV_E (v *m r x) = (rV_E v) ^ x.
Fact abelem_mx_repr : mx_repr G r.
Canonical abelem_repr := MxRepresentation abelem_mx_repr.
Let rG := abelem_repr.

Lemma rstabs_abelemG (L : {group gT}) :
L \subset E -> rstabs rG (rowg_mx (ErV @* L)) = 'N_G(L).