unfold ratDistance, maxRat, minRat in *.
intuition.
case_eq (bleRat r1 r2); intuition.
rewrite ratSubtract_0.
eapply rat0_le_all.
trivial.
Qed.

(* Specifications: *)
Lemma minRat_le_r : forall r1 r2,
minRat r1 r2 <= r2.