Goal:
    A : Type  v : A
  ============================
   (((∃ n : nat, hd_error (skipn n []) = Some v) → False)
    ∧ (False → ∃ n : nat, hd_error (skipn n []) = Some v))


DEBUG:Going to execute:
case not_locked_false_eq_true; Ltac.assumption
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Proof is not complete.
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Proof is not complete.
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Proof is not complete.
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Proof is not complete.
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Proof is not complete.