fpvandoorn/carleson
Source indexedtheorem · leanprover/lean4:v4.32.0
hasWeakType_maximalFunction_equal_exponents
Carleson.ToMathlib.HardyLittlewood · Carleson/ToMathlib/HardyLittlewood.lean:320 to 348
Mathematical statement
Exact Lean statement
theorem hasWeakType_maximalFunction_equal_exponents [BorelSpace X] [SeparableSpace X]
{p : ℝ≥0} (hp : 0 < p) :
HasWeakType (maximalFunction (E := E) μ 𝓑 c r p) p p μ μ (A ^ ((2 / p : ℝ)))Complete declaration
Lean source
Full Lean sourceLean 4
theorem hasWeakType_maximalFunction_equal_exponents [BorelSpace X] [SeparableSpace X] {p : ℝ≥0} (hp : 0 < p) : HasWeakType (maximalFunction (E := E) μ 𝓑 c r p) p p μ μ (A ^ ((2 / p : ℝ))) := by intro v mlpv constructor; · exact measurable_maximalFunction.aestronglyMeasurable have cp : 0 < (p : ℝ) := by positivity have p₁n : p ≠ 0 := by exact_mod_cast cp.ne' conv_lhs => enter [1, x] rw [maximalFunction_eq_maximalFunction_one_rpow cp] have hmb_one : wnorm (maximalFunction μ 𝓑 c r 1 (‖v ·‖ ^ (p : ℝ))) 1 μ ≤ ↑A ^ 2 * eLpNorm (fun x ↦ ‖v x‖ ^ (p : ℝ)) 1 μ := by apply (hasWeakType_maximalFunction_one (fun x : X ↦ ‖v x‖ ^ (p : ℝ)) _).2 convert! MemLp.norm_rpow_div mlpv p exact (ENNReal.div_self (coe_ne_zero.mpr p₁n) coe_ne_top).symm unfold wnorm wnorm' distribution at hmb_one ⊢ simp only [one_ne_top, ↓reduceIte, enorm_eq_self, toReal_one, inv_one, rpow_one, iSup_le_iff, coe_ne_top, coe_toReal] at hmb_one ⊢ intro t by_cases ht : t = 0 · rw [ht]; simp · apply (rpow_le_rpow_iff cp).mp rw [ENNReal.mul_rpow_of_nonneg _ _ NNReal.zero_le_coe] convert! hmb_one (t ^ (p : ℝ)) · exact (coe_rpow_of_ne_zero ht p).symm · rw [rpow_inv_rpow (NNReal.coe_ne_zero.mpr p₁n)] congr; ext x; rw [coe_rpow_of_ne_zero ht ↑p]; exact (lt_rpow_inv_iff cp) · rw [eLpNorm_norm_rpow v cp, ENNReal.mul_rpow_of_nonneg _ _ NNReal.zero_le_coe, div_eq_mul_inv, rpow_mul, rpow_inv_rpow (NNReal.coe_ne_zero.mpr p₁n), rpow_two]; simp