Class Monotone_exp :=
  monotone_exp : forall ex ey, (ex <= ey)%Z -> (fexp ex <= fexp ey)%Z.Class Monotone_exp :=
  monotone_exp : forall ex ey, (ex <= ey)%Z -> (fexp ex <= fexp ey)%Z.Global Instance monotone_exp_not_FTZ : Exp_not_FTZ.

Lemma canonic_exp_le_bpow : forall (x : R) (e : Z), x <> 0%R -> (Rabs x < bpow e)%R -> (canonic_exp x <= fexp e)%Z.