proposition: Lemma AQarctan_prf {a : AQ} : ¬0 ≤ a → 0 ≤ - a.
proof: Proof. intros. apply rings.flip_nonpos_negate. now apply orders.le_flip. Qed.
imports: CoRN.algebra.RSetoid CoRN.metric2.Metric CoRN.metric2.UniformContinuity CoRN.metric2.MetricMorphisms CoRN.reals.fast.CRarctan_small CoRN.reals.fast.CRarctan CoRN.reals.fast.CRpi_fast CoRN.reals.faster.ARpi CoRN.reals.faster.ARarctan_small CoRN.reals.faster.ARArith