OAI/Analysis/KadisonKastler/ProbabilityMatrixDistance.lean

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Distance to an algebra after vector integration

Diagonal amplification commutes with the actual vector integral. Applying the published complete commutant-distance bound to the commutant gives an algebra approximation without choosing measurable nearest points.

  1. theorem OAI.KadisonKastler.diagonalOperator_vector_measurable line 33

    Source documentation

    Finite diagonal amplification preserves vector measurability.

    theorem diagonalOperator_vector_measurable
        (μ : Measure S) (F : S → H →L[ℂ] H)
        (hF : ∀ x, AEStronglyMeasurable (fun s => F s x) μ) (n : ℕ) :
        ∀ x : Generator.FiniteHilbert (Fin n) H,
          AEStronglyMeasurable (fun s => Generator.diagonalOperator (F s) x) μ := by
    …

    Mentions: OAI.Generator.FiniteHilbert, OAI.Generator.diagonalOperator

  2. theorem OAI.KadisonKastler.norm_diagonalOperator_le line 49
  3. theorem OAI.KadisonKastler.probabilityOperatorIntegral_diagonal line 54
  4. theorem OAI.KadisonKastler.diagonal_commutes_commutant_matrix line 75

    Source documentation

    A matrix over the commutant commutes with each diagonal element of the algebra.

    theorem diagonal_commutes_commutant_matrix (M : VonNeumannAlgebra H)
        (b : H →L[ℂ] H) (hb : b ∈ M) (n : ℕ)
        (X : CStarMatrix (Fin n) (Fin n) (Algebra M.commutant)) :
        Generator.diagonalOperator b * matrixOperatorHom M.commutant X =
          matrixOperatorHom M.commutant X * Generator.diagonalOperator b := by
    …

    Mentions: OAI.KadisonKastler.Algebra, OAI.Generator.diagonalOperator, OAI.KadisonKastler.matrixOperatorHom

  5. theorem OAI.KadisonKastler.probabilityOperatorIntegral_complete_commutant_bound line 98

    Source documentation

    Pointwise algebra distance bounds pass to a complete commutator bound for the integral against the algebra's commutant.

    theorem probabilityOperatorIntegral_complete_commutant_bound
        (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)
        (M : VonNeumannAlgebra H) {δ : ℝ} (hδ : 0 ≤ δ)
        (hnear : ∀ᵐ s ∂μ, ∃ b : H →L[ℂ] H, b ∈ M ∧ ‖F s - b‖ ≤ δ) :
        CompletelyBoundedBy
          ((innerDerivation (probabilityOperatorIntegral μ F hF C hC)).comp
            M.commutant.toStarSubalgebra.subtype.toLinearMap) (2 * δ) := by
    …

    Mentions: OAI.KadisonKastler.CompletelyBoundedBy, OAI.KadisonKastler.innerDerivation, OAI.KadisonKastler.probabilityOperatorIntegral

  6. theorem OAI.KadisonKastler.exists_algebra_approximation_probabilityOperatorIntegral line 134

    Source documentation

    The published complete commutant-distance theorem supplies the needed algebra distance after integration, without any measurable selection.

    theorem exists_algebra_approximation_probabilityOperatorIntegral
        (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)
        (M : VonNeumannAlgebra H)
        (hDistance : PublishedBlockCommutantApproximation (Algebra M.commutant) H)
        {δ : ℝ} (hδ : 0 ≤ δ)
        (hnear : ∀ᵐ s ∂μ, ∃ b : H →L[ℂ] H, b ∈ M ∧ ‖F s - b‖ ≤ δ)
        (r : ℝ) (hr : δ < r) :
        ∃ b : H →L[ℂ] H, b ∈ M ∧
          ‖probabilityOperatorIntegral μ F hF C hC - b‖ < r := by
    …

    Mentions: OAI.KadisonKastler.PublishedBlockCommutantApproximation, OAI.KadisonKastler.Algebra, OAI.KadisonKastler.probabilityOperatorIntegral

  7. theorem OAI.KadisonKastler.infDist_probabilityOperatorIntegral_le line 152

    Source documentation

    Algebra distance is not increased by the vectorwise probability integral.

    theorem infDist_probabilityOperatorIntegral_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)
        (M : VonNeumannAlgebra H)
        (hDistance : PublishedBlockCommutantApproximation (Algebra M.commutant) H)
        {δ : ℝ} (hδ : 0 ≤ δ)
        (hnear : ∀ᵐ s ∂μ, Metric.infDist (F s) (M : Set (H →L[ℂ] H)) ≤ δ) :
        Metric.infDist (probabilityOperatorIntegral μ F hF C hC)
          (M : Set (H →L[ℂ] H)) ≤ δ := by
    …

    Mentions: OAI.KadisonKastler.PublishedBlockCommutantApproximation, OAI.KadisonKastler.Algebra, OAI.KadisonKastler.probabilityOperatorIntegral

  8. theorem OAI.KadisonKastler.infDist_measurablePoissonAverage_le line 177

    Source documentation

    The positive Poisson kernel retains an essential algebra-distance bound at every point above the real axis.

    theorem infDist_measurablePoissonAverage_le
        (F : ℝ → H →L[ℂ] H)
        (hF : ∀ x, AEStronglyMeasurable (fun s => F s x) volume)
        (C : ℝ) (hC : ∀ᵐ s, ‖F s‖ ≤ C)
        (M : VonNeumannAlgebra H)
        (hDistance : PublishedBlockCommutantApproximation (Algebra M.commutant) H)
        {δ : ℝ} (hδ : 0 ≤ δ)
        (hnear : ∀ᵐ s, Metric.infDist (F s) (M : Set (H →L[ℂ] H)) ≤ δ)
        (t r : ℝ) (hr : 0 < r) :
        Metric.infDist (measurablePoissonAverage F hF C hC t r hr)
          (M : Set (H →L[ℂ] H)) ≤ δ :=
    …

    Mentions: OAI.KadisonKastler.PublishedBlockCommutantApproximation, OAI.KadisonKastler.Algebra, OAI.KadisonKastler.measurablePoissonAverage

  9. theorem OAI.KadisonKastler.infDist_smul_algebra line 192

    Source documentation

    Scalar multiplication scales distance to the concrete complex algebra.

    theorem infDist_smul_algebra (M : VonNeumannAlgebra H) (z : ℂ)
        (T : H →L[ℂ] H) :
        Metric.infDist (z • T) (M : Set (H →L[ℂ] H)) =
          ‖z‖ * Metric.infDist T (M : Set (H →L[ℂ] H)) := by
    …