proposition: Lemma centvsP U V : reflect {in U & V, commutative *%R} (U <= 'C(V))%VS.
proof: Proof. by apply: (iffP subvP) => [cUV u v | cUV u] /cUV-/centvP; apply. 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)