proposition: Lemma F1_correct : Fchain_correct 1 F1.
proof: Proof. constructor; intros. cbn. split; reflexivity. Qed.
imports: Coq(List PArith Relations Lia) additions(Monoid_def Monoid_instances Strategies) Coq(Recdef Wf_nat) additions(More_on_positive Pow Euclidean_Chains Dichotomy BinaryStrat) Coq(NArith)