proposition: Lemma mulrDr : right_distributive mulU +%R.
proof: Proof. by move=> x y z; apply: val_inj; rewrite !(SubK, raddfD)/= !SubK mulrDr. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)