proposition: Lemma gcdr_eq0 a b : (gcdr a b == 0) = (a == 0) && (b == 0).
proof: Proof. by rewrite -!dvd0r dvdr_gcd. Qed.
imports: HB(structures) Coq(ssreflect ssrfun ssrbool Arith.Wf_nat) mathcomp(eqtype ssrnat div seq path) mathcomp(ssralg fintype perm tuple choice generic_quotient) mathcomp(matrix bigop zmodp mxalgebra poly) stronglydiscrete