proposition: Lemma coprimep_dvdl q p r : r %| q -> coprimep p q -> coprimep p r.
proof: Proof. move=> rp /coprimepP cpq'; apply/coprimepP => d dp dr. exact/cpq'/(dvdp_trans dr). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)