Definition Fweight (p : float) :=
  (Fnum p + Fexp p * Zpower_nat radix precision)%Z.

Theorem radixRangeBoundExp : forall p q : float, Fcanonic radix b p -> Fcanonic radix b q -> (0 <= p)%R -> (p < q)%R -> (q < radix * p)%R -> Fexp p = Fexp q \/ Zsucc (Fexp p) = Fexp q.