proposition: Lemma raddfZ_nat a u : a \is a nat_num -> f (a *: u) = a *: f u.
proof: Proof. by move=> /natrP[n ->]; apply: raddfZnat. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)