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fpvandoorn/carleson
Source indexedlemma · leanprover/lean4:v4.32.0

MeasureTheory.AESublinearOn.biSup2

Carleson.ToMathlib.RealInterpolation.Main · Carleson/ToMathlib/RealInterpolation/Main.lean:284 to 321

Mathematical statement

Exact Lean statement

lemma biSup2 {ι : Type*} {𝓑 : Set ι} (h𝓑 : 𝓑.Countable) {T : ι → (α → ε₁) → α' → ℝ≥0∞}
    {P : (α → ε₁) → Prop} {Q : (α → ε₁) → Prop}
    (hPT : ∀ (u : α → ε₁), P u → ∀ᵐ x ∂ν, ⨆ i ∈ 𝓑, T i u x ≠ ∞)
    (hQT : ∀ (u : α → ε₁), Q u → ∀ᵐ x ∂ν, ⨆ i ∈ 𝓑, T i u x ≠ ∞)
    (P0 : P 0)
    (Q0 : Q 0)
    (haP : ∀ {f g : α → ε₁}, P f → P g → P (f + g))
    (haQ : ∀ {f g : α → ε₁}, Q f → Q g → Q (f + g))
    (hsP : ∀ {f : α → ε₁} {c : ℝ≥0}, P f → P (c • f))
    (hsQ : ∀ {f : α → ε₁} {c : ℝ≥0}, Q f → Q (c • f))
    {A : ℝ≥0} -- todo, here and elsewhere: probably better to have {A : ℝ≥0∞} (hA : A ≠ ⊤)
    (hAP : ∀ i ∈ 𝓑,
      AESublinearOn (T i) (fun g ↦ g ∈ {f | P f} + {f | Q f}) A ν) :
    AESublinearOn (fun u x ↦ ⨆ i ∈ 𝓑, T i u x) (fun f ↦ P f ∨ Q f) A ν

Complete declaration

Lean source

Canonical source
Full Lean sourceLean 4
lemma biSup2 {ι : Type*} {𝓑 : Set ι} (h𝓑 : 𝓑.Countable) {T : ι  ε₁)  α'  0∞}    {P : (α  ε₁)  Prop} {Q : (α  ε₁)  Prop}    (hPT :  (u : α  ε₁), P u  ᵐ x ∂ν, ⨆ i  𝓑, T i u x  ∞)    (hQT :  (u : α  ε₁), Q u  ᵐ x ∂ν, ⨆ i  𝓑, T i u x  ∞)    (P0 : P 0)    (Q0 : Q 0)    (haP :  {f g : α  ε₁}, P f  P g  P (f + g))    (haQ :  {f g : α  ε₁}, Q f  Q g  Q (f + g))    (hsP :  {f : α  ε₁} {c : 0}, P f  P (c • f))    (hsQ :  {f : α  ε₁} {c : 0}, Q f  Q (c • f))    {A : 0} -- todo, here and elsewhere: probably better to have {A : ℝ≥0∞} (hA : A ≠ ⊤)    (hAP :  i  𝓑,      AESublinearOn (T i) (fun g  g  {f | P f} + {f | Q f}) A ν) :    AESublinearOn (fun u x  ⨆ i  𝓑, T i u x) (fun f  P f  Q f) A ν := by  set R := fun g  g  {f | P f} + {f | Q f}  have hPR :  {f}, P f  R f := fun hu  _, hu, 0, Q0, by simp  have hQR :  {f}, Q f  R f := fun hu  0, P0, _, hu, by simp  apply AESublinearOn.antitone (P' := R) (fun hu  hu.elim hPR hQR)  refine AESublinearOn.biSup (P := R) h𝓑 ?_ ?_ ?_ hAP  · rintro _ f, hf, g, hg, rfl    filter_upwards [hPT f hf, hQT g hg,      AESubadditiveOn.forall_le h𝓑 (fun i hi  hAP i hi |>.1) (hPR hf) (hQR hg)] with x hfx hgx hTx    simp_rw [ lt_top_iff_ne_top] at hfx hgx     simp_rw [enorm_eq_self] at hTx    calc      _  ⨆ i  𝓑, A * (T i f x + T i g x) := by gcongr; exact hTx _ ‹_›      _  A * ((⨆ i  𝓑, T i f x) + (⨆ i  𝓑, T i g x)) := by          simp_rw [ ENNReal.mul_iSup]          gcongr          -- todo: make lemma          simp_rw [iSup_le_iff]          intro i hi          gcongr <;> apply le_biSup _ hi      _ <:= mul_lt_top coe_lt_top <| add_lt_top.mpr hfx, hgx  · rintro _ _ f₁, hf₁, g₁, hg₁, rfl f₂, hf₂, g₂, hg₂, rfl    exact f₁ + f₂, haP hf₁ hf₂, g₁ + g₂, haQ hg₁ hg₂, by dsimp only; abel_nf  · rintro _ c f, hf, g, hg, rfl    exact c • f, hsP hf, c • g, hsQ hg, by module