OAI/NumberTheory/DukePrimeDegree/Dynamics/CompactFamilyGeneric.lean

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A fixed generic set for a compact family of observables

The limiting shear is selected after the generic set. Compactness of the possible shears gives a compact family of translated observables in the uniform norm. A finite approximation therefore suffices for one common generic set and time threshold. No commutation of the translating group with the averaging flow is required.

  1. theorem OAI.DukePrimeDegree.exists_finite_uniform_real_flow_generic_set line 22
  2. lemma OAI.DukePrimeDegree.flow_average_error_of_uniform_approximation line 58
  3. theorem OAI.DukePrimeDegree.exists_compact_family_real_flow_generic_set line 115

    Source documentation

    Compactness is in the uniform norm on bounded continuous functions.

    theorem exists_compact_family_real_flow_generic_set
        {Y : Type*} [TopologicalSpace Y] [MeasurableSpace Y] [BorelSpace Y]
        [MulAction (Multiplicative ℝ) Y] [ContinuousSMul (Multiplicative ℝ) Y]
        (μ : Measure Y) [IsProbabilityMeasure μ] [ErgodicSMul (Multiplicative ℝ) Y μ]
        (K : Set (Y →ᵇ ℝ)) (hK : IsCompact K)
        (ε δ : ℝ) (hε : 0 < ε) (hδ : 0 < δ) :
        ∃ G : Set Y, MeasurableSet G ∧ μ Gᶜ ≤ ENNReal.ofReal δ ∧
          ∃ R : ℝ, 1 ≤ R ∧ ∀ x ∈ G, ∀ f ∈ K, ∀ T ≥ R,
            |T⁻¹ * (∫ t in (0 : ℝ)..T, f (realActionTime t x)) -
              ∫ y, f y ∂μ| ≤ ε := by
    …

    Mentions: OAI.DukePrimeDegree.realActionTime

  4. def OAI.DukePrimeDegree.compactObservableTranslate line 142
  5. theorem OAI.DukePrimeDegree.continuous_compactObservableTranslate line 148
  6. theorem OAI.DukePrimeDegree.exists_compact_translate_real_flow_generic_set line 167

    Source documentation

    The translating element may be any later-selected point of a fixed compact set. It is unrelated to the real averaging flow.

    theorem exists_compact_translate_real_flow_generic_set
        {H Y : Type*} [Group H] [TopologicalSpace H] [IsTopologicalGroup H]
        [WeaklyLocallyCompactSpace H] [TopologicalSpace Y]
        [MulAction H Y] [ContinuousSMul H Y]
        [MeasurableSpace Y] [BorelSpace Y]
        [MulAction (Multiplicative ℝ) Y] [ContinuousSMul (Multiplicative ℝ) Y]
        (μ : Measure Y) [IsProbabilityMeasure μ] [ErgodicSMul (Multiplicative ℝ) Y μ]
        (f : CompactlySupportedContinuousMap Y ℝ) (K : Set H) (hK : IsCompact K)
        (ε δ : ℝ) (hε : 0 < ε) (hδ : 0 < δ) :
        ∃ G : Set Y, MeasurableSet G ∧ μ Gᶜ ≤ ENNReal.ofReal δ ∧
          ∃ R : ℝ, 1 ≤ R ∧ ∀ x ∈ G, ∀ a ∈ K, ∀ T ≥ R,
            |T⁻¹ * (∫ t in (0 : ℝ)..T, f (a • realActionTime t x)) -
    …

    Mentions: OAI.DukePrimeDegree.realActionTime