fact: Variables (l r: Qpos) (x y: CR).
imports: CoRN.algebra.RSetoid CoRN.metric2.Metric CoRN.metric2.UniformContinuity Coq.QArith.QArith CoRN.model.totalorder.QposMinMax CoRN.model.metric2.Qmetric CoRN.reals.fast.CRArith