proposition: Lemma dvdr_gcd : forall d a b, d %| gcdr a b = (d %| a) && (d %| b) :> bool.
proof: Proof. exact: gcdr_subdef. 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