Proof with auto with typeclass_instances.
apply generic_inclusion_le...
intros e He.
unfold FIX_exp.
apply Zmax_lub.
omega.
apply Zle_refl.
Qed.

Theorem ulp_FLT_small: forall x, (Rabs x < bpow (emin+prec))%R ->
ulp beta FLT_exp x = bpow emin.