proposition: Lemma rt_step' {X : Type} (R : X -> X -> Prop) x y z : R x y -> clos_refl_trans _ R y z -> clos_refl_trans _ R x z.
proof: Proof. by eauto using clos_refl_trans. Qed.
imports: Undecidability.LambdaCalculus(Krivine Lambda Util.Krivine_facts) Undecidability.LambdaCalculus.Util.term_facts Undecidability.Shared.deterministic_simulation Relations List ssreflect