proposition: Lemma gcdz_idPr {m n} : reflect (gcdz m n = `|n|%:Z) (n %| m)%Z.
proof: Proof. by rewrite gcdzC; apply: gcdz_idPl. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop prime order) mathcomp(ssralg poly ssrnum ssrint archimedean rat matrix) mathcomp(polydiv perm zmodp mxalgebra vector)