proposition: Lemma lead_coefN p : lead_coef (- p) = - lead_coef p.
proof: Proof. by rewrite /lead_coef size_opp coefN. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype bigop finset tuple) mathcomp(div ssralg countalg binomial)