proposition: Lemma dvdp_gcd_idr m n : n %| m -> gcdp m n %= n.
proof: Proof. by move/dvdp_gcd_idl; exact/eqp_trans/gcdpC. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)