Section Rlt_bool.
Definition Rlt_bool x y :=
match Rcompare x y with
| Lt => true
| _ => false
end.
Inductive Rlt_bool_prop (x y : R) : bool -> Prop :=
| Rlt_bool_true_ : (x < y)%R -> Rlt_bool_prop x y true
| Rlt_bool_false_ : (y <= x)%R -> Rlt_bool_prop x y false.

Lemma Rlt_bool_opp :
forall x y,
Rlt_bool (- x) (- y) = Rlt_bool y x.