intros x y Hx Hy H1 H2; unfold Fulp in |- *.
apply Rle_powerRZ; auto with real zarith.
apply Fcanonic_Rle_Zle with radix b precision; auto with zarith arith.
apply FnormalizeCanonic; auto with zarith arith.
apply FnormalizeCanonic; auto with zarith arith.
repeat rewrite FnormalizeCorrect; auto with zarith arith real.
repeat rewrite Rabs_right; auto with zarith arith real.
apply Rge_trans with (FtoRradix x); auto with real.
Qed.

Theorem FulpSucCan :
forall p : float,
Fcanonic radix b p -> (FSucc b radix precision p - p <= Fulp p)%R.