proposition: Lemma mulcC : commutative mulc.
proof: Proof. move=> [a b] [c d] /=. by rewrite [c * b + _]addrC ![_ * c]mulrC ![_ * d]mulrC. Qed.
imports: HB(structures) mathcomp.ssreflect.ssreflect mathcomp(ssrfun ssrbool eqtype ssrnat seq choice fintype) mathcomp(bigop order ssralg ssrint div ssrnum rat poly closed_field) mathcomp(polyrcf matrix mxalgebra tuple mxpoly zmodp binomial realalg) mathcomp(mxpoly)