proposition: Lemma memberE m (I : 'cV[R]_m) (a : R) : member a I = (a%:M <= I)%IS :> bool.
proof: Proof. by apply/memberP/subidP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq path) mathcomp(ssralg fintype perm choice fingroup) mathcomp(matrix bigop zmodp mxalgebra poly) ssrcomplements