fact: Definition Q_as_MetricSpace : MetricSpace := @Build_MetricSpace Q _ Qball_e_wd Q_is_MetricSpace.
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