fpvandoorn/carleson
Source indexedlemma · leanprover/lean4:v4.32.0
carlesonOperator_eq_biSup_Θ'_J102
Carleson.MetricCarleson.Main · Carleson/MetricCarleson/Main.lean:25 to 70
Mathematical statement
Exact Lean statement
lemma carlesonOperator_eq_biSup_Θ'_J102 {x : X} (mf : Measurable f) (nf : (‖f ·‖) ≤ 1) :
carlesonOperator K f x =
⨆ θ ∈ Θ' X, ⨆ j ∈ J102, ‖carlesonOperatorIntegrand K θ j.1 j.2 f x‖ₑComplete declaration
Lean source
Full Lean sourceLean 4
lemma carlesonOperator_eq_biSup_Θ'_J102 {x : X} (mf : Measurable f) (nf : (‖f ·‖) ≤ 1) : carlesonOperator K f x = ⨆ θ ∈ Θ' X, ⨆ j ∈ J102, ‖carlesonOperatorIntegrand K θ j.1 j.2 f x‖ₑ := by unfold carlesonOperator linearizedCarlesonOperator; apply le_antisymm · refine iSup_le fun θ ↦ iSup₂_le fun R₁ R₂ ↦ iSup₂_le fun hR₁ hR₂ ↦ ?_ refine ENNReal.le_of_forall_pos_le_add fun ε εpos ltt ↦ ?_ rw [← NNReal.coe_pos] at εpos -- Shift `θ` to an element of `Θ'` with error less than `ε / 2` have tcon := @continuous_carlesonOperatorIntegrand _ _ _ _ _ R₁ R₂ _ x mf nf hR₁ rw [continuous_iff] at tcon; specialize tcon θ _ (half_pos εpos) obtain ⟨δ₀, δ₀pos, dθ⟩ := tcon have dΘ' := dense_Θ' (X := X) rw [dense_iff] at dΘ'; specialize dΘ' θ _ δ₀pos; obtain ⟨θ', mθ'₁, mθ'₂⟩ := dΘ' rw [mem_ball] at mθ'₁; specialize dθ _ mθ'₁ -- Shift `R₁, R₂` to rationals with error less than `ε / 2` obtain ⟨q₁, q₂, lq₁, lq, -, dq⟩ := exists_rat_near_carlesonOperatorIntegrand θ' x mf nf hR₁ hR₂ (half_pos εpos) -- Combine `dq` and `dθ` have final_bound := (dist_triangle ..).trans_lt (add_lt_add dq dθ) rw [add_halves] at final_bound calc _ = ‖carlesonOperatorIntegrand K θ' q₁ q₂ f x + (carlesonOperatorIntegrand K θ R₁ R₂ f x - carlesonOperatorIntegrand K θ' q₁ q₂ f x)‖ₑ := by rw [add_sub_cancel] _ ≤ ‖carlesonOperatorIntegrand K θ' q₁ q₂ f x‖ₑ + edist (carlesonOperatorIntegrand K θ' q₁ q₂ f x) (carlesonOperatorIntegrand K θ R₁ R₂ f x) := by rw [edist_comm, edist_eq_enorm_sub] exact enorm_add_le _ _ _ ≤ _ := by gcongr · calc _ ≤ ⨆ j ∈ J102, ‖carlesonOperatorIntegrand K θ' j.1 j.2 f x‖ₑ := by have : (q₁, q₂) ∈ J102 := ⟨Rat.cast_pos.mp (hR₁.trans lq₁), lq⟩ convert! le_iSup₂ _ this; rfl _ ≤ _ := by apply le_iSup₂ _ mθ'₂ · rw [edist_dist, coe_nnreal_eq]; exact ofReal_le_ofReal final_bound.le · refine iSup₂_le fun θ mθ ↦ iSup₂_le fun ⟨q₁, q₂⟩ ⟨hq₁, hq₂⟩ ↦ ?_ conv_rhs => enter [1, θ, 1, R₁]; rw [iSup_comm] simp_rw [← Rat.cast_lt (K := ℝ), Rat.cast_zero] at hq₁ hq₂ calc _ ≤ ⨆ (R₂ : ℝ), ⨆ (_ : q₁ < R₂), ‖carlesonOperatorIntegrand K θ q₁ R₂ f x‖ₑ := by convert! le_iSup₂ _ hq₂; rfl _ ≤ ⨆ (R₁ : ℝ), ⨆ (_ : 0 < R₁), ⨆ R₂, ⨆ (_ : R₁ < R₂), ‖carlesonOperatorIntegrand K θ R₁ R₂ f x‖ₑ := by convert! le_iSup₂ _ hq₁; rfl _ ≤ _ := le_iSup_iff.mpr fun _ a ↦ a θ