fact: Definition Ball X R := prod X R.
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 util.Container