proposition: Lemma mulc_addl : left_distributive (@mulc R) (@addc R).
proof: Proof. move=> [a b] [c d] [e f] /=; rewrite !mulrDl !opprD -!addrA. by congr ((_ + _) +i* (_ + _)); rewrite addrCA. 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)