proposition: Lemma Qball_0_r (e: Qpos) : Qball (proj1_sig e) (proj1_sig e) 0.
proof: Proof. Proof with auto with qarith. apply Qball_Qabs. unfold Qminus. rewrite Qplus_0_r. rewrite Qabs_pos... Qed.
imports: CoRN.metric2.Metric CoRN.metric2.Prelength CoRN.metric2.Classification CoRN.model.totalorder.QMinMax CoRN.model.totalorder.QposMinMax Coq.QArith.Qabs CoRN.metric2.UniformContinuity MathClasses.implementations.stdlib_rationals