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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

Canonical 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 : ) := simpleNontangentialOperator K (n + 1 : )⁻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 : ), 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 : )⁻¹ < R := inv_lt_of_inv_lt₀ hR <| Nat.le_ceil R⁻¹ |>.trans_lt (by linarith)    let seq (n : ) := ⨆ (_ : (n + 1 : )⁻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