proposition: Theorem IMSELL3_undec : undecidable (@IMSELL_cf_PROVABILITY imsell3).
proof: Proof. refine (@IMSELL_undec (exist _ imsell3 _)). now exists (Some true), (Some false), None. Qed.
imports: Undecidability.Synthetic.Undecidability Undecidability.MinskyMachines(ndMM2 ndMM2_undec) Undecidability.ILL(IMSELL ndMM2_IMSELL)