proposition: Lemma CRabs_nonneg (x: CR): 0 <= CRabs x.
proof: Proof. intro e. simpl. unfold Cap_raw; simpl. rewrite Qplus_0_r. apply (Qle_trans _ 0). apply (Qopp_le_compat 0), Qpos_nonneg. apply Qabs_nonneg. Qed.
imports: CoRN.algebra.RSetoid CoRN.metric2.Metric CoRN.metric2.UniformContinuity CoRN.model.totalorder.QposMinMax CoRN.reals.fast.CRArith CoRN.model.metric2.Qmetric Coq.QArith.Qabs CoRN.model.totalorder.QMinMax CoRN.logic.Stability