proposition: Lemma ℤle_realizer : forall e, ℤle↓e ⊩ ∀₂n,m∈ℤ×ℤ, ∀ A B, ((n <= m)%Z ↦ A) → ((~n <= m)%Z ↦ B) → ((n <= m)%Z ↦ A) ∩ ((~n <= m)%Z ↦ B).
proof: Proof. intro e. start; destruct (Z_le_dec n m); Ksolve; contradiction. Qed.
imports: ZArith ClassicalRealizability.Kbase