Section Zlt_bool.
Inductive Zlt_bool_prop (x y : Z) : bool -> Prop :=
| Zlt_bool_true_ : (x < y)%Z -> Zlt_bool_prop x y true
| Zlt_bool_false_ : (y <= x)%Z -> Zlt_bool_prop x y false.

Theorem negb_Zle_bool :
forall x y : Z,
negb (Zle_bool x y) = Zlt_bool y x.