Definition Fulp (p : float) :=
  powerRZ radix (Fexp (Fnormalize radix b precision p)).

Theorem FulpLe2 : forall p : float, Fbounded b p -> Fnormal radix b (Fnormalize radix b precision p) -> (Fulp p <= Rabs p * powerRZ radix (Zsucc (- precision)))%R.