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(** * Decidability of equality and order on Z *)
Notation dec_Zle := Z.le_decidable (only parsing).
Notation dec_Zlt := Z.lt_decidable (only parsing).

Theorem not_Zeq n m : n <> m -> n < m \/ m < n.
Notation Zgt_iff_lt := Z.gt_lt_iff (only parsing).