proposition: Lemma rmorphXn n : {morph f : x / x ^+ n}.
proof: Proof. by elim: n => [|n IHn] x; rewrite ?rmorph1 // !exprS rmorphM IHn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop prime binomial)