(** ** Specific uniform spaces *)
(** Rings with absolute value *)
Section AbsRing_UniformSpace.
Variable K : AbsRing.
Definition AbsRing_ball (x : K) (eps : R) (y : K) := abs (minus y x) < eps.

Lemma AbsRing_ball_sym :
forall (x y : K) (e : R),
AbsRing_ball x e y -> AbsRing_ball y e x.