proposition: Lemma gcdp_modr m n : gcdp m (n %% m) %= gcdp m n.
proof: Proof. apply: eqp_trans (gcdpC _ _); apply: eqp_trans (gcdp_modl _ _); exact: gcdpC. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop ssralg poly)