OAI/NumberTheory/DukePrimeDegree/Entropy/SubexponentialCoverAlphabet.lean

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5 declarations, 0 contain sorry, 0 declared as axioms

Subexponential coding cost for a height-bounded covering alphabet

  1. def OAI.DukePrimeDegree.coverAlphabet line 14
  2. lemma OAI.DukePrimeDegree.mem_coverAlphabet line 17
  3. lemma OAI.DukePrimeDegree.coverAlphabet_card_le line 25
  4. lemma OAI.DukePrimeDegree.coverAlphabet_log_card_le line 47
  5. theorem OAI.DukePrimeDegree.ae_coverAlphabet_cost_tendsto_zero line 64

    Source documentation

    Encoding one height-bounded label anywhere in the word costs o(N). The same alphabet covers every time in the window.

    theorem ae_coverAlphabet_cost_tendsto_zero {Y : Type*} [MeasurableSpace Y]
        (μ : Measure Y) [IsFiniteMeasure μ] {T : Y → Y} (hT : MeasurePreserving T μ μ)
        (H Q : Y → ℕ) (hH : Measurable H) (hstep : ∀ x, H (T x) ≤ H x+1)
        (J : ℕ → ℕ) {K C : ℝ} (hK : 0 < K) (hC : 0 ≤ C)
        (hJ : ∀ m, (J m:ℝ) ≤ K*Real.exp (C*(m:ℝ)))
        (hcode : ∀ m, Q '' {x | H x=m} ⊆ (Nat.pair m) '' Set.Iio (J m)) :
        ∀ᵐ x ∂μ,
          (∀ N k, k ≤ N → Q (T^[k] x) ∈ coverAlphabet J (windowHeight T H N x)) ∧
          Tendsto (fun N : ℕ => Real.log (coverAlphabet J (windowHeight T H N x)).card / N)
            atTop (𝓝 0) := by
    …

    Mentions: OAI.DukePrimeDegree.coverAlphabet, OAI.DukePrimeDegree.windowHeight