This file contains the Carleson-Hunt theorem, a generalization of classical_carleson.
theorem
exceptional_set_carleson
{f : ℝ → ℂ}
(periodic_f : Function.Periodic f (2 * Real.pi))
{q : ENNReal}
(hq : 1 < q)
(hf : MeasureTheory.MemLp f q (MeasureTheory.volume.restrict (Set.Ioc 0 (2 * Real.pi))))
{δ ε : NNReal}
(δpos : 0 < δ)
(εpos : 0 < ε)
:
∃ (N₀ : ℕ),
MeasureTheory.distribution (fun (x : ℝ) => ⨆ (N : ℕ), ⨆ (_ : N > N₀), ‖f x - partialFourierSum N f x‖ₑ) (↑δ)
(MeasureTheory.volume.restrict (Set.Ioc 0 (2 * Real.pi))) ≤ ↑ε
theorem
carleson_hunt_interval
{f : ℝ → ℂ}
(periodic_f : Function.Periodic f (2 * Real.pi))
{p : ENNReal}
(hp : 1 < p)
(hf : MeasureTheory.MemLp f p (MeasureTheory.volume.restrict (Set.Ioc 0 (2 * Real.pi))))
:
∀ᵐ (x : ℝ) ∂MeasureTheory.volume.restrict (Set.Ioc 0 (2 * Real.pi)), Filter.Tendsto (fun (x_1 : ℕ) => partialFourierSum x_1 f x) Filter.atTop (nhds (f x))
theorem
carleson_hunt_real
{f : ℝ → ℂ}
(periodic_f : Function.Periodic f (2 * Real.pi))
{p : ENNReal}
(hp : 1 < p)
(hf : MeasureTheory.MemLp f p (MeasureTheory.volume.restrict (Set.Ioc 0 (2 * Real.pi))))
:
∀ᵐ (x : ℝ), Filter.Tendsto (fun (x_1 : ℕ) => partialFourierSum x_1 f x) Filter.atTop (nhds (f x))
theorem
carleson_hunt_two_pi
{f : AddCircle (2 * Real.pi) → ℂ}
{p : ENNReal}
(hp : 1 < p)
(hf : MeasureTheory.MemLp f p MeasureTheory.volume)
:
∀ᵐ (x : AddCircle (2 * Real.pi)), Filter.Tendsto (fun (x_1 : ℕ) => (partialFourierSum' x_1 f) x) Filter.atTop (nhds (f x))
theorem
carleson_hunt'
{T : ℝ}
[hT : Fact (0 < T)]
{f : AddCircle T → ℂ}
{p : ENNReal}
(hp : 1 < p)
(hf : MeasureTheory.MemLp f p MeasureTheory.volume)
:
∀ᵐ (x : AddCircle T), Filter.Tendsto (fun (x_1 : ℕ) => (partialFourierSum' x_1 f) x) Filter.atTop (nhds (f x))
theorem
carleson_hunt
{T : ℝ}
[hT : Fact (0 < T)]
{f : AddCircle T → ℂ}
{p : ENNReal}
(hp : 1 < p)
(hf : MeasureTheory.MemLp f p AddCircle.haarAddCircle)
:
∀ᵐ (x : AddCircle T), Filter.Tendsto (fun (x_1 : ℕ) => (partialFourierSum' x_1 f) x) Filter.atTop (nhds (f x))
Classical theorem of Carleson and Hunt asserting a.e. convergence of the partial Fourier sums
for L^p functions for p > 1. This is a strengthening of classical_carleson, and not officially
part of the blueprint.