proposition: Lemma agenvS U V : (U <= V -> agenv U <= agenv V)%VS.
proof: Proof. move=> sUV; rewrite agenv_sub_modl ?sub1_agenv //. by rewrite -[Vs in (_ <= Vs)%VS]agenvM prodvSl ?(subv_trans sUV) ?sub_agenv. 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)