proposition: Lemma rmorph_sign n : f ((- 1) ^+ n) = (- 1) ^+ n.
proof: Proof. by rewrite rmorphXn /= rmorphN1. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)