proposition: Lemma dvdr_mem_gcds (l : seq R) x : x \in l -> gcdsr l %| x.
proof: Proof. by move=> hx; move: (dvdrr (gcdsr l)); rewrite dvdr_gcds; move/allP; apply. 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