proposition: Lemma subv_cent1 U v : (U <= 'C[v])%VS = (v \in 'C(U)%VS).
proof: Proof. by apply/subvP/centvP=> cUv u Uu; apply/cent1vP; rewrite 1?cent1vC cUv. 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)