proposition: Lemma eqEsubv U V : (U == V) = (U <= V <= U)%VS.
proof: Proof. by apply/eqP/idP=> [-> | /subv_anti//]; rewrite subvv. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)