fpvandoorn/carleson
Source indexedtheorem · leanprover/lean4:v4.32.0
simple_nontangential_operator_le
Carleson.TwoSidedCarleson.NontangentialOperator · Carleson/TwoSidedCarleson/NontangentialOperator.lean:796 to 834
Source documentation
This is the first step of the proof of Lemma 10.0.2, and should follow from 10.1.6 +
monotone convergence theorem. (measurability should be proven without any restriction on r.)
Exact Lean statement
theorem simple_nontangential_operator_le (ha : 4 ≤ a)
(hT : ∀ r > 0, HasBoundedStrongType (czOperator K r) 2 2 volume volume (C_Ts a)) (hr : 0 ≤ r) :
HasBoundedStrongType (simpleNontangentialOperator K r) 2 2 volume volume (C10_1_6 a)Complete declaration
Lean source
Full Lean sourceLean 4
theorem simple_nontangential_operator_le (ha : 4 ≤ a) (hT : ∀ r > 0, HasBoundedStrongType (czOperator K r) 2 2 volume volume (C_Ts a)) (hr : 0 ≤ r) : HasBoundedStrongType (simpleNontangentialOperator K r) 2 2 volume volume (C10_1_6 a) := by by_cases h : 0 < r · exact simple_nontangential_operator ha hT h have : r = 0 := by linarith rw [this] intro g hg constructor · exact aestronglyMeasurable_simpleNontangentialOperator let f (n : ℕ) := simpleNontangentialOperator K (n + 1 : ℝ)⁻¹ g have f_mon (x : X): Monotone fun n ↦ f n x := by intro m n hmn; simp only unfold f simpleNontangentialOperator gcongr with R simp_rw [gt_iff_lt] apply iSup_const_mono (lt_of_le_of_lt _) rw [inv_le_inv₀ (by positivity) (by positivity)] simp [hmn] have snt0 : (fun x => ⨆ (n : ℕ), f n x) = simpleNontangentialOperator K 0 g := by ext x unfold f simpleNontangentialOperator simp_rw [gt_iff_lt]; rw [iSup_comm] congr with R apply le_antisymm (iSup_le <| fun n ↦ iSup_const_mono (lt_trans (by positivity))) (iSup_le _) intro hR let n := Nat.ceil R⁻¹ have hn : (n + 1 : ℝ)⁻¹ < R := inv_lt_of_inv_lt₀ hR <| Nat.le_ceil R⁻¹ |>.trans_lt (by linarith) let seq (n : ℕ) := ⨆ (_ : (n + 1 : ℝ)⁻¹ < R), ⨆ x' ∈ ball x R, ‖czOperator K R g x'‖ₑ have : ⨆ x' ∈ ball x R, ‖czOperator K R g x'‖ₑ = seq n := by unfold seq; rw [iSup_pos hn] nth_rw 1 [this] exact le_iSup seq n have mct := eLpNorm_iSup' (p := 2) (f := f) (μ := volume) (fun n ↦ aestronglyMeasurable_simpleNontangentialOperator.aemeasurable) (by filter_upwards; exact f_mon) rw [← snt0, mct] apply iSup_le intro n; unfold f apply simple_nontangential_operator ha hT (by positivity) g hg |>.2