Definition Fminus (x y : float) := Fplus x (Fopp y).

(* Specifications: *)
Theorem Fminus_correct : forall x y : float, Fminus x y = (x - y)%R :>R.
Theorem Fopp_Fminus : forall p q : float, Fopp (Fminus p q) = Fminus q p.
Theorem Fopp_Fminus_dist : forall p q : float, Fopp (Fminus p q) = Fminus (Fopp p) (Fopp q).
Theorem minusSameExp : forall x y : float, Fexp x = Fexp y -> Fminus x y = Float (Fnum x - Fnum y) (Fexp x).