fact: Definition ACball (u v : AR*AR) (e : Q) : Prop := 0 <= e /\ ARle ((fst u - fst v)*(fst u - fst v) + (snd u - snd v)*(snd u - snd v)) (inject_Q_AR (e*e)).
imports: CoRN.algebra.RSetoid CoRN.metric2.Metric CoRN.metric2.UniformContinuity Coq.QArith.Qabs CoRN.model.metric2.Qmetric CoRN.metric2.ProductMetric CoRN.model.totalorder.QposMinMax CoRN.model.totalorder.QMinMax CoRN.reals.faster.ARabs CoRN.reals.faster.ARroot CoRN.reals.faster.ARArith