OAI/Analysis/KadisonKastler/ProbabilityOperatorRelations.lean

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Linear relations and commutator bounds under vector integration

The operator fields are only assumed measurable on each vector. Fixed left and right multiplication commute with their probability integral; essential operator-norm commutator bounds therefore pass to the integral.

  1. theorem OAI.KadisonKastler.ae_norm_operator_sandwich_le line 23

    Source documentation

    An explicit bound for a fixed sandwich of a bounded field.

    theorem ae_norm_operator_sandwich_le
        (μ : Measure S) (F : S → H →L[ℂ] H) {C : ℝ}
        (hF : ∀ᵐ s ∂μ, ‖F s‖ ≤ C) (A B : H →L[ℂ] H) :
        ∀ᵐ s ∂μ, ‖A * F s * B‖ ≤ ‖A‖ * C * ‖B‖ := by
    …
  2. theorem OAI.KadisonKastler.probabilityOperatorIntegral_sandwich line 35

    Source documentation

    Fixed operator multiplication commutes with the actual vector integral.

    theorem probabilityOperatorIntegral_sandwich
        (μ : Measure S) [IsProbabilityMeasure μ]
        (F : S → H →L[ℂ] H) (hF : ∀ x, AEStronglyMeasurable (fun s => F s x) μ)
        (C : ℝ) (hC : ∀ᵐ s ∂μ, ‖F s‖ ≤ C) (A B : H →L[ℂ] H) :
        probabilityOperatorIntegral μ (fun s => A * F s * B)
          (fun x => A.continuous.comp_aestronglyMeasurable (hF (B x)))
          (‖A‖ * C * ‖B‖) (ae_norm_operator_sandwich_le μ F hC A B) =
          A * probabilityOperatorIntegral μ F hF C hC * B := by
    …

    Mentions: OAI.KadisonKastler.probabilityOperatorIntegral, OAI.KadisonKastler.ae_norm_operator_sandwich_le

  3. theorem OAI.KadisonKastler.norm_probabilityOperatorIntegral_commutator_le line 49

    Source documentation

    A uniform almost-everywhere commutator bound survives vector integration.

    theorem norm_probabilityOperatorIntegral_commutator_le
        (μ : Measure S) [IsProbabilityMeasure μ]
        (F : S → H →L[ℂ] H) (hF : ∀ x, AEStronglyMeasurable (fun s => F s x) μ)
        (C : ℝ) (hC : ∀ᵐ s ∂μ, ‖F s‖ ≤ C) (A : H →L[ℂ] H)
        {ε : ℝ} (hε : 0 ≤ ε)
        (hcomm : ∀ᵐ s ∂μ, ‖F s * A - A * F s‖ ≤ ε) :
        ‖probabilityOperatorIntegral μ F hF C hC * A -
          A * probabilityOperatorIntegral μ F hF C hC‖ ≤ ε := by
    …

    Mentions: OAI.KadisonKastler.probabilityOperatorIntegral

  4. theorem OAI.KadisonKastler.norm_commutator_of_near_commuting line 73

    Source documentation

    An algebra approximation bounds every commutator with its commutant.

    theorem norm_commutator_of_near_commuting
        (T b A : H →L[ℂ] H) {δ : ℝ} (hTb : ‖T - b‖ ≤ δ)
        (hbA : b * A = A * b) : ‖T * A - A * T‖ ≤ 2 * δ * ‖A‖ := by
    …
  5. theorem OAI.KadisonKastler.norm_probabilityOperatorIntegral_commutator_of_near line 90

    Source documentation

    This estimate requires no measurable choice of nearby algebra elements.

    theorem norm_probabilityOperatorIntegral_commutator_of_near
        (μ : Measure S) [IsProbabilityMeasure μ]
        (F : S → H →L[ℂ] H) (hF : ∀ x, AEStronglyMeasurable (fun s => F s x) μ)
        (C : ℝ) (hC : ∀ᵐ s ∂μ, ‖F s‖ ≤ C) (A : H →L[ℂ] H)
        {δ : ℝ} (hδ : 0 ≤ δ)
        (hnear : ∀ᵐ s ∂μ, ∃ b : H →L[ℂ] H, b * A = A * b ∧ ‖F s - b‖ ≤ δ) :
        ‖probabilityOperatorIntegral μ F hF C hC * A -
          A * probabilityOperatorIntegral μ F hF C hC‖ ≤ 2 * δ * ‖A‖ := by
    …

    Mentions: OAI.KadisonKastler.probabilityOperatorIntegral