proposition: Lemma precoeff_reduce x s : precoeff x (reduce s) = precoeff x s.
proof: Proof. by rewrite !precoeffE prelift_reduce. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order generic_quotient) mathcomp(ssralg ssrnum ssrint)