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diff --git a/matita/matita/tests/bad_induction.ma b/matita/matita/tests/bad_induction.ma
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+(**************************************************************************)
+(*       ___                                                              *)
+(*      ||M||                                                             *)
+(*      ||A||       A project by Andrea Asperti                           *)
+(*      ||T||                                                             *)
+(*      ||I||       Developers:                                           *)
+(*      ||T||         The HELM team.                                      *)
+(*      ||A||         http://helm.cs.unibo.it                             *)
+(*      \   /                                                             *)
+(*       \ /        This file is distributed under the terms of the       *)
+(*        v         GNU General Public License Version 2                  *)
+(*                                                                        *)
+(**************************************************************************)
+
+
+
+include "nat/nat.ma".
+
+include "logic/equality.ma".
+
+axiom bad_ind : ∀P : nat -> Prop. ∀n.(n = O -> P n) -> (∀n.P n -> P (S n)) -> P n.
+
+theorem absurd: ∀n. n = O.
+  intros.
+  letin P ≝ (λx:nat. n = O).
+  apply (bad_ind P n); simplify; intros; unfold; autobatch.
+qed.
\ No newline at end of file