fpvandoorn/carleson
Source indexedlemma · leanprover/lean4:v4.32.0
distribution_czOperatorBound
Carleson.TwoSidedCarleson.WeakCalderonZygmund · Carleson/TwoSidedCarleson/WeakCalderonZygmund.lean:1594 to 1643
Source documentation
Lemma 10.2.8
Exact Lean statement
lemma distribution_czOperatorBound (ha : 4 ≤ a) (hf : BoundedFiniteSupport f)
(hα : ⨍⁻ x, ‖f x‖ₑ / c10_0_3 a < α) (hX : GeneralCase f (α' a α)) :
volume ((Ω f (α' a α))ᶜ ∩ czOperatorBound hX ⁻¹' Ioi (α / 8)) ≤
C10_2_8 a / α * eLpNorm f 1 volumeComplete declaration
Lean source
Full Lean sourceLean 4
lemma distribution_czOperatorBound (ha : 4 ≤ a) (hf : BoundedFiniteSupport f) (hα : ⨍⁻ x, ‖f x‖ₑ / c10_0_3 a < α) (hX : GeneralCase f (α' a α)) : volume ((Ω f (α' a α))ᶜ ∩ czOperatorBound hX ⁻¹' Ioi (α / 8)) ≤ C10_2_8 a / α * eLpNorm f 1 volume := by rcases eq_zero_or_pos α with rfl | αpos; · simp at hα rcases eq_top_or_lt_top α with rfl | αlt · have : czOperatorBound hX ⁻¹' Ioi (⊤ / 8) = ∅ := by rw [top_div_of_ne_top (by norm_num), isMax_top.Ioi_eq, preimage_empty] rw [this, inter_empty, measure_empty]; exact zero_le calc _ ≤ (volume.restrict (Ω f (α' a α))ᶜ) {x | α / 8 ≤ czOperatorBound hX x} := by rw [inter_comm, ← Measure.restrict_apply']; swap · apply MeasurableSet.compl; simp_rw [Ω, hX, dite_true] exact MeasurableSet.iUnion fun _ ↦ measurableSet_ball gcongr; intro x mx; simp only [mem_preimage, mem_Ioi, mem_setOf_eq] at mx ⊢; exact mx.le _ ≤ (∫⁻ x in (Ω f (α' a α))ᶜ, czOperatorBound hX x) / (α / 8) := by apply meas_ge_le_lintegral_div · refine ((AEMeasurable.tsum fun i ↦ ?_).const_mul _).restrict refine AEMeasurable.div ?_ measurable_vol₁.aemeasurable refine ((AEMeasurable.const_div ?_ _).pow_const _).mul_const _ simp only [coe_nnreal_ennreal_nndist] exact aemeasurable_id'.edist aemeasurable_const · simp [αpos.ne'] · finiteness _ ≤ 8 * C10_2_7 a * ∑' i, volume (czBall3 hX i) * ∫⁻ x in (Ω f (α' a α))ᶜ, ((3 * czRadius hX i).toNNReal / edist x (czCenter hX i)) ^ (a : ℝ)⁻¹ / volume (ball x (dist x (czCenter hX i))) := by unfold czOperatorBound rw [lintegral_const_mul' _ _ (by finiteness), ENNReal.div_eq_inv_mul, ENNReal.inv_div (.inr αlt.ne) (.inr αpos.ne'), ← mul_assoc, ← mul_assoc, ← ENNReal.mul_div_right_comm, ENNReal.div_mul_cancel αpos.ne' αlt.ne] simp only [coe_nnreal_ennreal_nndist] rw [lintegral_tsum]; swap · refine fun i ↦ (AEMeasurable.div ?_ measurable_vol₁.aemeasurable).restrict refine ((AEMeasurable.const_div ?_ _).pow_const _).mul_const _ exact aemeasurable_id'.edist aemeasurable_const congr! 3 with i rw [← lintegral_const_mul' _ _ (by finiteness)]; congr 2 with x rw [← ENNReal.mul_comm_div, mul_div_assoc, mul_comm] _ ≤ 8 * C10_2_7 a * ∑' i, volume (czBall3 hX i) * 2 ^ (3 * a) := by gcongr with i; exact czOperatorBound_inner_le ha hX _ ≤ 8 * C10_2_7 a * 2 ^ (3 * a) * (2 ^ (4 * a) / α' a α * eLpNorm f 1 volume) := by rw [ENNReal.tsum_mul_right, mul_comm _ (2 ^ _), ← mul_assoc]; gcongr exact tsum_volume_czBall3_le hf hX (α'_pos αpos) _ = _ := by rw [← mul_assoc, ← mul_div_assoc, show (8 : ℝ≥0∞) * C10_2_7 a * 2 ^ (3 * a) * 2 ^ (4 * a) = 2 ^ (7 * a + 3) * C10_2_7 a by ring, C10_2_7, coe_mul, ← mul_assoc, div_α'_eq, ENNReal.mul_div_cancel_right (by rw [c10_0_3]; positivity) (by rw [c10_0_3]; finiteness), show (2 : ℝ≥0∞) = (2 : ℝ≥0) by rfl, ← coe_pow, ← coe_mul, ← pow_add, C10_2_8] congr 4; ring