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fpvandoorn/carleson
Source indexedlemma · leanprover/lean4:v4.32.0

lintegral_carlesonSum_forest'

Carleson.Discrete.ForestUnion · Carleson/Discrete/ForestUnion.lean:796 to 831

Source documentation

For each forest, the integral of the norm of the Carleson sum can be controlled thanks to the forest theorem and to the density control coming from the fact we are away from G₁. Second version, with the volume of F.

Exact Lean statement

lemma lintegral_carlesonSum_forest'
    {f : X → ℂ} (hf : Measurable f) (h2f : ∀ x, ‖f x‖ ≤ F.indicator 1 x) :
    ∫⁻ x in G \ G', ‖carlesonSum (⋃ u ∈ 𝔘₄ k n j l, 𝔗₂ k n j u) f x‖ₑ ≤
    C2_0_4 a q n * 2 ^ (a + 5/2 : ℝ) * (volume G) ^ (1 - q⁻¹) * (volume F) ^ (q⁻¹)

Complete declaration

Lean source

Canonical source
Full Lean sourceLean 4
lemma lintegral_carlesonSum_forest'    {f : X  ℂ} (hf : Measurable f) (h2f :  x, ‖f x‖  F.indicator 1 x) :    ∫⁻ x in G \ G', ‖carlesonSum (⋃ u  𝔘₄ k n j l, 𝔗₂ k n j u) f x‖ₑ     C2_0_4 a q n * 2 ^ (a + 5/2 : ) * (volume G) ^ (1 - q⁻¹) * (volume F) ^ (q⁻¹) := by  apply (lintegral_carlesonSum_forest hf h2f).trans  simp only [mul_assoc]  apply mul_le_mul_right  simp only [div_eq_mul_inv, one_mul, ENNReal.mul_rpow_of_nonneg _ _ (inv_q_sub_half_nonneg X),     ENNReal.rpow_natCast,  ENNReal.rpow_mul]  calc  2 ^ ((2 * a + 5 : ) * (q⁻¹ - 2⁻¹)) * volume F ^ (q⁻¹ - 2⁻¹) * (volume G)⁻¹ ^ (q⁻¹ - 2⁻¹) *    (volume F ^ (2⁻¹ : ) * volume G ^ (2⁻¹ : ))  _  2 ^ (a + 5/2 : ) * volume F ^ (q⁻¹ - 2⁻¹) * (volume G)⁻¹ ^ (q⁻¹ - 2⁻¹) *    ((volume F) ^ (2⁻¹ : ) * volume G ^ (2⁻¹ : )) := by    gcongr    · exact one_le_two    have : 1  q := (one_lt_q X).le    have : (2 * a + 5 : ) * (q⁻¹ - 2⁻¹)  (2 * a + 5 : ) * (1⁻¹ - 2⁻¹) := by gcongr    apply this.trans_eq    norm_num    simp [add_mul, div_eq_mul_inv]    ring  _ = 2 ^ (a + 5/2 : ) * (volume G ^ (1 - q⁻¹) * volume F ^ q⁻¹) := by    rcases eq_or_ne (volume G) 0 with vG | vG    · have : 0 < 1 - q⁻¹ := by rw [sub_pos, inv_lt_one_iff₀]; exact .inr (one_lt_q X)      rw [vG, ENNReal.zero_rpow_of_pos (by positivity), ENNReal.zero_rpow_of_pos this]      simp only [zero_mul, mul_zero]    · have IF : (volume F) ^ (q⁻¹) = (volume F) ^ ((q ⁻¹ - 2⁻¹) + 2⁻¹) := by congr; abel      have IG : (volume G) ^ (1 - q⁻¹) = (volume G) ^ (2⁻¹ - (q⁻¹ - 2⁻¹)) := by        congr 1        simp only [sub_sub_eq_add_sub, sub_left_inj]        norm_num      rw [IF, IG, ENNReal.rpow_sub _ _ vG volume_G_ne_top,        ENNReal.rpow_add_of_nonneg (x := volume F) _ _ (inv_q_sub_half_nonneg X) (by norm_num),        ENNReal.div_eq_inv_mul, ENNReal.inv_rpow]      ring