proposition: Fact derivn_is_linear n : linear (derivn n).
proof: Proof. by elim: n => // n IHn a p q; rewrite derivnS IHn linearP. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)