fpvandoorn/carleson
Source indexedtheorem · leanprover/lean4:v4.32.0
linearizedCarlesonOperator_measurable
Carleson.MetricCarleson.Basic · Carleson/MetricCarleson/Basic.lean:514 to 574
Mathematical statement
Exact Lean statement
@[fun_prop]
theorem linearizedCarlesonOperator_measurable {θ : Θ X} (hf : LocallyIntegrable f) :
Measurable (linearizedCarlesonOperator (fun _ ↦ θ) K f)Complete declaration
Lean source
Full Lean sourceLean 4
@[fun_prop]theorem linearizedCarlesonOperator_measurable {θ : Θ X} (hf : LocallyIntegrable f) : Measurable (linearizedCarlesonOperator (fun _ ↦ θ) K f) := by unfold linearizedCarlesonOperator have {x : X} : ⨆ R₁, ⨆ R₂, ⨆ (_ : 0 < R₁), ⨆ (_ : R₁ < R₂), ‖carlesonOperatorIntegrand K ((fun x ↦ θ) x) R₁ R₂ f x‖ₑ = ⨆ (R₁ : ℚ), ⨆ (R₂ : ℚ), ⨆ (_ : 0 < R₁), ⨆ (_ : R₁ < R₂), ‖carlesonOperatorIntegrand K ((fun x ↦ θ) x) R₁ R₂ f x‖ₑ := by apply le_antisymm · apply le_of_forall_lt_imp_le_of_dense intro c hc rw [lt_iSup_iff] at hc rcases hc with ⟨R₁, h⟩ rw [lt_iSup_iff] at h rcases h with ⟨R₂, h⟩ rw [lt_iSup_iff] at h rcases h with ⟨R₁_pos, h⟩ rw [lt_iSup_iff] at h rcases h with ⟨R₁_lt_R₂, h⟩ set ε := ‖carlesonOperatorIntegrand K ((fun x ↦ θ) x) R₁ R₂ f x‖ - c.toReal have ε_pos : 0 < ε := by unfold ε apply sub_pos_of_lt apply toReal_lt_of_lt_ofReal rwa [ofReal_norm] have mf : IntegrableOn f (Annulus.oo x R₁ R₂) volume := by apply IntegrableOn.mono_set _ (Annulus.oo_subset_ball) apply IntegrableOn.mono_set _ (ball_subset_closedBall) apply hf.integrableOn_isCompact (isCompact_closedBall _ _) have exist_rats := exists_rat_near_carlesonOperatorIntegrand' θ x mf R₁_pos R₁_lt_R₂ ε_pos rcases exist_rats with ⟨q₁, q₂, R₁_lt_q₁, q₁_lt_q₂, q₂_lt_R₂, h_dist⟩ have q₁_pos : (0 : ℝ) < q₁ := R₁_pos.trans R₁_lt_q₁ simp only [Rat.cast_pos] at q₁_pos apply le_iSup₂_of_le q₁ q₂ apply le_iSup₂_of_le q₁_pos q₁_lt_q₂ rw [dist_eq_norm] at h_dist have c_ne_top := h.ne_top rw [← ofReal_norm, lt_ofReal_iff_toReal_lt c_ne_top] at h have : c.toReal = ‖carlesonOperatorIntegrand K ((fun x ↦ θ) x) R₁ R₂ f x‖ - ε := by simp [ε] rw [← ofReal_norm, le_ofReal_iff_toReal_le c_ne_top (by simp), this] have : ‖carlesonOperatorIntegrand K ((fun x ↦ θ) x) R₁ R₂ f x‖ ≤ ε + ‖carlesonOperatorIntegrand K ((fun x ↦ θ) x) q₁ q₂ f x‖ := by simp only apply le_trans _ (add_le_add_left h_dist.le _) rw [add_comm] apply norm_le_norm_add_norm_sub apply le_trans (sub_le_sub_right this _) simp · apply iSup_le intro q₁ apply iSup_le intro q₂ apply iSup_le intro q₁_pos apply iSup_le intro q₁_lt_q₂ apply le_iSup₂_of_le (Rat.cast q₁) (Rat.cast q₂) apply le_iSup₂_of_le (by simpa) (by simpa) rfl simp_rw [this] have := hf.aestronglyMeasurable fun_prop