proposition: Fact Op_gcdz_subproof n m : Z_of_int (gcdz n m) = Z.gcd (Z_of_int n) (Z_of_int m).
proof: Proof. rewrite /gcdz -Z.gcd_abs_l -Z.gcd_abs_r; lia. Qed.
imports: Coq(ZArith ZifyClasses ZifyBool) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(div choice fintype tuple finfun bigop finset prime) mathcomp(order binomial ssralg countalg ssrnum ssrint rat) mathcomp(intdiv) mathcomp(zify_ssreflect ssrZ)