proposition: Lemma prodv_sub U V A : (U <= A -> V <= A -> U * V <= A)%VS.
proof: Proof. by move=> sUA sVA; rewrite -prodv_id prodvS. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype div tuple finfun bigop ssralg) mathcomp(finalg zmodp matrix vector poly)