fact: Definition Eball (q: Q) (x y: X'): Prop := ball q (f x) (f y).
imports: CoRN.metric2.Metric CoRN.model.totalorder.QposMinMax Coq.Setoids.Setoid CoRN.stdlib_omissions.Q CoRN.model.totalorder.QMinMax CoRN.metric2.Complete CoRN.metric2.Prelength MathClasses.interfaces.abstract_algebra