proposition: Lemma enc_injective n m: enc n = enc m -> n = m.
proof: Proof. injection 1 as H. induction n in m, H |-*; destruct m; try discriminate; trivial. erewrite IHn; trivial. injection H; eauto. Qed.
imports: List Lia Undecidability.HOU(std.std calculus.calculus second_order.diophantine_equations) Undecidability.HOU.unification(systemunification nth_order_unification)