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(*   Copyright Dominique Larchey-Wendling [*]                 *)
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(*                             [*] Affiliation LORIA -- CNRS  *)
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(*      This file is distributed under the terms of the       *)
(*         CeCILL v2 FREE SOFTWARE LICENSE AGREEMENT          *)
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From Undecidability.MinskyMachines
From Undecidability.ILL
Local Infix "≤" := (@IMSELL_le _) (at level 70).
Local Notation "u ≰ v" := (~ u ≤ v) (at level 70).
Local Notation U := (@IMSELL_U _).
(* Undecidability of IMSELL3, ie IMSELL with 3 modalities {a,b,∞} with a,b < ∞ and ∞ is the only universal modality *)

Theorem IMSELL_undec (S : IMSELL_sig3) : undecidable (@IMSELL_cf_PROVABILITY3 S).