fpvandoorn/carleson
Source indexedtheorem · leanprover/lean4:v4.32.0
hasStrongType_maximalFunction
Carleson.ToMathlib.HardyLittlewood · Carleson/ToMathlib/HardyLittlewood.lean:292 to 318
Source documentation
The maximalFunction has strong type when p₁ < p₂.
Exact Lean statement
public theorem hasStrongType_maximalFunction
[BorelSpace X] [IsFiniteMeasureOnCompacts μ] [ProperSpace X] [μ.IsOpenPosMeasure]
{p₁ p₂ : ℝ≥0} (hp₁ : 0 < p₁) (hp₁₂ : p₁ < p₂) :
HasStrongType (maximalFunction (E := E) μ 𝓑 c r p₁) p₂ p₂ μ μ (C2_0_6 A p₁ p₂)Complete declaration
Lean source
Full Lean sourceLean 4
public theorem hasStrongType_maximalFunction [BorelSpace X] [IsFiniteMeasureOnCompacts μ] [ProperSpace X] [μ.IsOpenPosMeasure] {p₁ p₂ : ℝ≥0} (hp₁ : 0 < p₁) (hp₁₂ : p₁ < p₂) : HasStrongType (maximalFunction (E := E) μ 𝓑 c r p₁) p₂ p₂ μ μ (C2_0_6 A p₁ p₂) := by by_cases h : Nonempty X; swap · have := not_nonempty_iff.mp h; intro _ _; simp intro v mlpv refine ⟨measurable_maximalFunction.aestronglyMeasurable, ?_⟩ have cp₁p : 0 < (p₁ : ℝ) := by positivity have p₁n : p₁ ≠ 0 := by exact_mod_cast cp₁p.ne' conv_lhs => enter [1, x] rw [maximalFunction_eq_maximalFunction_one_rpow cp₁p, ← enorm_eq_self (maximalFunction ..)] rw [eLpNorm_enorm_rpow _ (by positivity), ENNReal.ofReal_inv_of_pos cp₁p, ENNReal.ofReal_coe_nnreal, ← div_eq_mul_inv, ← ENNReal.coe_div p₁n] calc _ ≤ (CMB A (p₂ / p₁) * eLpNorm (fun y ↦ ‖v y‖ ^ (p₁ : ℝ)) (p₂ / p₁) μ) ^ p₁.toReal⁻¹ := by apply ENNReal.rpow_le_rpow _ (by positivity) convert (hasStrongType_maximalFunction_one (μ := μ) _ (fun x ↦ ‖v x‖ ^ (p₁ : ℝ)) _).2 · rw [ENNReal.coe_div p₁n] · rwa [lt_div_iff₀, one_mul]; exact cp₁p · rw [ENNReal.coe_div p₁n]; exact mlpv.norm_rpow_div p₁ _ = _ := by rw [ENNReal.mul_rpow_of_nonneg _ _ (by positivity), eLpNorm_norm_rpow _ cp₁p, ENNReal.ofReal_coe_nnreal, ENNReal.div_mul_cancel (by positivity) (by simp), ENNReal.rpow_rpow_inv (by positivity), ← ENNReal.coe_rpow_of_nonneg _ (by positivity), C2_0_6]