OAI/MeasureTheory/Falconer/Angular/AngularBootstrap.lean

GitHub source file

2 declarations, 0 contain sorry, 0 declared as axioms

Endpoint of the thin-tube bootstrap

This is the order-theoretic step in Proposition prep:thin-upgrade. Its hypotheses describe the closed set of available exponents inside [k - 1, k - 1 / 2], with strict improvement below the endpoint.

  1. theorem OAI.Falconer.thin_tube_bootstrap_endpoint line 21

    Source documentation

    A closed family of available exponents containing the integer starting exponent and admitting a strict improvement below the desired endpoint contains the half-integer endpoint.

    theorem thin_tube_bootstrap_endpoint (k : ℕ) (A : Set ℝ)
        (hclosed : IsClosed A) (hstart : (k : ℝ) - 1 ∈ A)
        (hupper : ∀ q ∈ A, q ≤ (k : ℝ) - 1 / 2)
        (himprove : ∀ q ∈ A, q < (k : ℝ) - 1 / 2 → ∃ q' ∈ A, q < q') :
        (k : ℝ) - 1 / 2 ∈ A := by
    …
  2. theorem OAI.Falconer.cap_exponent_loss_transfer line 38

    Source documentation

    At resolution R⁻¹, increasing the cap exponent by at most e costs only the allowed factor R ^ e. This is the quantitative inequality used when closing the set of available exponents in prep:thin-upgrade.

    theorem cap_exponent_loss_transfer {R u q q' e : ℝ}
        (hR : 1 ≤ R) (hu : R⁻¹ ≤ u) (hqq : q ≤ q') (hgap : q' - q ≤ e) :
        u ^ q ≤ R ^ e * u ^ q' := by
    …