proposition: Lemma neq_equiv1 : forall e, λ"x" "x" @ Id↓e ⊩ ∀a a', ¬(prop (a = a')) → a ≠ a'.
proof: Proof. Ksolve. destruct (Peano_dec.eq_nat_dec a a'). unfold prop in *. start. destruct Hπ as [[_ Hπ] | [Hc _]]. unfold one in *. Ksolve. contradiction. elim Hπ. Qed.
imports: ClassicalRealizability.Kbase