proposition: Lemma eqp_mul2r r p q : r != 0 -> (p * r %= q * r) = (p %= q).
proof: Proof. by move=> nz_r; rewrite /eqp !dvdp_mul2r. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)