fact: Definition genball: MetricSpaceBall X := λ (oe: Qinf), match oe with | Qinf.infinite => λ _ _, True | Qinf.finite e => match Qdec_sign e with | inl (inl _) => λ _ _ , False | inl (inr p) => R (exist (Qlt 0) e p) | inr _ => equiv end end.
imports: CoRN.algebra.RSetoid Arith List CoRN.model.totalorder.QposMinMax CSetoids Qmetric Qring Qinf QnnInf QnonNeg ProductMetric QposInf Qposclasses UniformContinuity MathClasses.implementations.stdlib_rationals stdlib_omissions.Pair stdlib_omissions.Q PointFree MathClasses.interfaces.abstract_algebra MathClasses.theory.setoids MathClasses.theory.products