proposition: Lemma coeffMn z n : {morph coeff z: x / x *+ n} .
proof: Proof. exact: raddfMn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)