Goal:
    A : Type  v : A
  ============================
   ((∃ _ : nat, hd_error [] = Some v) ↔ False)


DEBUG:Going to execute:
cbn
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil
DEBUG LTAC Evaluated term: skipn_nil