Definition Fmult (x y : float) := Float (Fnum x * Fnum y) (Fexp x + Fexp y).Definition Fmult_correct : forall x y : float, Fmult x y = (x * y)%R :>R.

Theorem oneZplus : forall x y : Z, Float 1%nat (x + y) = Fmult (Float 1%nat x) (Float 1%nat y).