proposition: Lemma derivX : ('X)^`() = 1.
proof: Proof. by apply/polyP=> [[|i]]; rewrite coef_deriv coef1 coefX ?mul0rn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)