proposition: Lemma divp_pmul2r p q : lead_coef p \in GRing.unit -> q * d %/ (p * d) = q %/ p.
proof: Proof. by move=> uq; rewrite -!(mulrC d) divp_pmul2l. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)