OAI/Analysis/LipschitzHilbert/Estimates/WeightedAverage.lean

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The cellwise weighted averaging step in §10.

  1. theorem OAI.LipschitzHilbert.weighted_average_le line 18

    Source documentation

    A nonnegative factor of average at most one may be integrated against a weight comparable to a constant, with the same comparison loss.

    theorem weighted_average_le (μ : Measure α) [IsFiniteMeasure μ]
        (w f : α → ℝ) {c C : ℝ} (hc : 0 ≤ c) (hC : 0 ≤ C)
        (hw : AEStronglyMeasurable w μ) (hf : Integrable f μ)
        (hf0 : ∀ᵐ x ∂μ, 0 ≤ f x)
        (hlower : ∀ᵐ x ∂μ, c ≤ w x)
        (hupper : ∀ᵐ x ∂μ, w x ≤ C * c)
        (haverage : (∫ x, f x ∂μ) ≤ μ.real Set.univ) :
        Integrable (fun x => w x * f x) μ ∧
          (∫ x, w x * f x ∂μ) ≤ C * ∫ x, w x ∂μ := by
    …
  2. theorem OAI.LipschitzHilbert.weighted_nested_average_le line 53

    Source documentation

    The actual product of nested normalized predictions admits the same weighted cell estimate.

    theorem weighted_nested_average_le [Fintype κ]
        (μ : Measure α) [IsFiniteMeasure μ]
        (P : ℕ → α → κ) (R : ℕ → κ → κ) (g : ℕ → κ → ℝ)
        (N : ℕ) (w : α → ℝ) {c C : ℝ} (hc : 0 ≤ c) (hC : 0 ≤ C)
        (hw : AEStronglyMeasurable w μ)
        (hlower : ∀ᵐ x ∂μ, c ≤ w x) (hupper : ∀ᵐ x ∂μ, w x ≤ C * c)
        (hP : ∀ n ≤ N, ∀ i, MeasurableSet {x | P n x = i})
        (hrefine : ∀ n < N, ∀ x, P n x = R n (P (n + 1) x))
        (hg : ∀ n < N, ∀ i, 0 ≤ g n i)
        (haverage : ∀ n < N, ∀ i,
          (∫ x in {x | P n x = i}, g n (P (n + 1) x) ∂μ) ≤ μ.real {x | P n x = i}) :
        Integrable (fun x => w x * ∏ j ∈ Finset.range N, g j (P (j + 1) x)) μ ∧
    …