proposition: Lemma scaler_nat n v : n%:R *: v = v *+ n.
proof: Proof. elim: n => /= [|n]; first by rewrite scale0r. by rewrite !mulrS scalerDl ?scale1r => ->. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)