proposition: Lemma scalpE p q : scalp p q = 0.
proof: Proof. have [-> | qn0] := eqVneq q 0; first by rewrite scalp0. by rewrite Idomain.scalpE unitfE lead_coef_eq0 qn0. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)