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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‖ₑ

Complete declaration

Lean source

Canonical 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 := ), Rat.cast_zero] at hq₁ hq₂    calc      _  ⨆ (R₂ : ), ⨆ (_ : q₁ < R₂),          ‖carlesonOperatorIntegrand K θ q₁ R₂ f x‖ₑ := by convert! le_iSup₂ _ hq₂; rfl      _  ⨆ (R₁ : ), ⨆ (_ : 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