proposition: Lemma euclid_gcdl a b c : coprimer a b -> gcdr a (b * c) %= gcdr a c.
proof: Proof. by move=> cab; rewrite mulrC euclid_gcdr. 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