proposition: Lemma expvS U V n : (U <= V -> U ^+ n <= V ^+ n)%VS.
proof: Proof. move=> sUV; elim: n => [|n IHn]; first by rewrite !expv0 subvv. by rewrite !expvSl 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)