proposition: Lemma not_impl3_realizer : forall e, not_impl3↓e ⊩ ∀A B C D, ¬(A → B → C → D) → (A ∧ B ∧ C ∧ ¬D).
proof: Proof. Ksolve. startn 1. now eapply callcc_other_realizer; find. startn 1. eapply (callcc_other_realizer _ (C → D)); find. do 2 Ksolve. startn 1. eapply callcc_other_realizer; find. do 2 Ksolve. eok. do 2 Ksolve. Qed.
imports: ClassicalRealizability.Tactics ClassicalRealizability.BasicResults ClassicalRealizability.Subtyping