Local Notation "'Zm" := (scale_action _ _) (at level 8) : action_scope.
Section RowGroup.
Variable n : nat.
Local Notation rVn := 'rV[F]_n.
Definition rowg m (A : 'M[F]_(m, n)) : {set rVn} := [set u | u <= A]%MS.

Lemma mem_rowg m A v : (v \in @rowg m A) = (v <= A)%MS.
Canonical rowg_group m A := Group (@rowg_group_set m A).