fpvandoorn/carleson
Source indexedlemma · leanprover/lean4:v4.32.0
iLipENorm_holderApprox'
Carleson.HolderVanDerCorput · Carleson/HolderVanDerCorput.lean:445 to 480
Mathematical statement
Exact Lean statement
lemma iLipENorm_holderApprox' {z : X} {R t : ℝ} (ht : 0 < t) (h't : t ≤ 1)
{C : ℝ≥0} {φ : X → ℂ} (hc : Continuous φ) (hφ : φ.support ⊆ ball z R) (hC : ∀ x, ‖φ x‖ ≤ C) :
iLipENorm (holderApprox R t φ) z (2 * R) ≤
2 ^ (4 * a) * (ENNReal.ofReal t) ^ (-1 - a : ℝ) * CComplete declaration
Lean source
Full Lean sourceLean 4
lemma iLipENorm_holderApprox' {z : X} {R t : ℝ} (ht : 0 < t) (h't : t ≤ 1) {C : ℝ≥0} {φ : X → ℂ} (hc : Continuous φ) (hφ : φ.support ⊆ ball z R) (hC : ∀ x, ‖φ x‖ ≤ C) : iLipENorm (holderApprox R t φ) z (2 * R) ≤ 2 ^ (4 * a) * (ENNReal.ofReal t) ^ (-1 - a : ℝ) * C := by let C' : ℝ≥0 := 2 ^ (4 * a) * (t.toNNReal) ^ (-1 - a : ℝ) * C have : 2 ^ (4 * a) * (ENNReal.ofReal t) ^ (-1 - a : ℝ) * C = C' := by simp only [ENNReal.coe_mul, ENNReal.coe_pow, ENNReal.coe_ofNat, C', ENNReal.ofReal] congr rw [ENNReal.coe_rpow_of_ne_zero] simpa using ht rw [this] apply iLipENorm_le · intro x hx have h'R : 0 < 2 * R := pos_of_mem_ball hx have hR : 0 < R := by linarith apply (holderApprox_le hR ht hC x).trans simp only [NNReal.coe_mul, NNReal.coe_pow, NNReal.coe_ofNat, NNReal.coe_rpow, C', ← mul_assoc] have : (C : ℝ) = 1 * 1 * C := by simp conv_lhs => rw [this] gcongr · calc (1 : ℝ) _ = 2⁻¹ * (2 ^ 1) := by norm_num _ ≤ 2⁻¹ * (2 ^ (4 * a)) := by gcongr · norm_num · have := four_le_a X linarith · apply Real.one_le_rpow_of_pos_of_le_one_of_nonpos (by simp [ht]) (by simp [h't]) linarith · intro x hx x' hx' hne have h'R : 0 < 2 * R := pos_of_mem_ball hx have hR : 0 < R := by linarith simp only [NNReal.coe_mul, NNReal.coe_pow, NNReal.coe_ofNat, NNReal.coe_rpow, Real.coe_toNNReal', ht.le, sup_of_le_left, ← mul_assoc, C'] exact norm_holderApprox_sub_le hR ht h't hc hφ hC