proposition: Lemma dvdr_gcdl a b : gcdr a b %| a.
proof: Proof. by move: (dvdrr (gcdr a b)); rewrite dvdr_gcd; case/andP. 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