proposition: Lemma normal_form_enc_nat n : normal_form (enc_nat n).
proof: Proof. elim: n; by do ? constructor. Qed.
imports: Undecidability.LambdaCalculus(Krivine Lambda Util.Krivine_facts) Undecidability.LambdaCalculus.Util.term_facts Undecidability.Shared.deterministic_simulation Relations List ssreflect