proposition: Lemma hausdorffBall_refl : forall (e:Q) A, 0 <= e -> hausdorffBall e A A.
proof: Proof. intros e A epos. split. exact epos. split; apply hemiMetric_refl; exact epos. Qed.
imports: CoRN.algebra.RSetoid CoRN.logic.Classic CoRN.metric2.Metric CoRN.metric2.Classification Coq.Lists.List Coq.ZArith.ZArith CoRN.model.totalorder.QMinMax CoRN.model.totalorder.QposMinMax