(* Stabilisers, etc, are only mapped properly for fields. *)
Section FieldRepr.
Variable F : fieldType.
Section OneRepresentation.
Variable gT : finGroupType.
Variables (G : {group gT}) (n : nat) (rG : mx_representation F G n).
Arguments rG _%group_scope : extra scopes.
Local Notation E_G := (enveloping_algebra_mx rG).

Lemma rstab_act x m1 (W : 'M_(m1, n)) :
x \in rstab rG U -> (W <= U)%MS -> W *m rG x = W.