OAI/Analysis/KadisonKastler/BoundaryPolarMeasurable.lean
3 declarations, 0 contain sorry, 0 declared as axioms
Measurability of the diagonal unitary polar field
The polar factor is a Lipschitz function of a near-identity operator in its tracial Hilbert realization. Factoring through the range of the measurable least field therefore supplies its measurability.
- theorem
OAI.KadisonKastler.aestronglyMeasurable_polar_traceline 29Source documentation
A uniformly near-identity field has measurable unitary polar factors whenever the original field is measurable in its tracial Hilbert space.
theorem aestronglyMeasurable_polar_trace (τ : FaithfulTracialState B) (J : B →ₗ[ℂ] E) (hJ : ∀ x, ‖J x‖ = traceTwoNorm τ x) {μ : Measure P} (c : P → B) (a : P → unitary B) {r : ℝ} (hr : r < 1) (hnear : ∀ p, ‖c p - 1‖ ≤ r) (hpolar : ∀ p, (a p : B) * CFC.abs (c p) = c p) (hmeas : AEStronglyMeasurable (fun p => J (c p)) μ) : AEStronglyMeasurable (fun p => J (a p : B)) μ := by …Mentions: OAI.KadisonKastler.FaithfulTracialState, OAI.KadisonKastler.traceTwoNorm
- theorem
OAI.KadisonKastler.exists_measurable_diagonal_unitary_comparisonline 83Source documentation
The diagonal comparison unitary is itself measurable in the trace Hilbert realization, in addition to its exact covariance and norm bound.
theorem exists_measurable_diagonal_unitary_comparison (J : Algebra M →ₗ[ℂ] E) (hJ : ∀ x, ‖J x‖ = traceTwoNorm τ x) (hτ : FiniteVectorTrace τ) {G D : Type*} [Group G] [Countable G] [MeasurableSpace D] {μ : Measure (D × D)} (shift : G → D → D) (W : G → D → unitary (Algebra M)) (hW : ∀ g t x, (W (g * t) x : Algebra M) = (W g x : Algebra M) * (W t (shift g x) : Algebra M)) (hWmeas : ∀ t, AEStronglyMeasurable (fun p : D × D => J ((W t p.1 : Algebra M) * star (W t p.2 : Algebra M))) μ) {r : ℝ} (hr0 : 0 ≤ r) (hr : r < 1) (hnear : ∀ t x y, ‖(W t x : Algebra M) * star (W t y : Algebra M) - 1‖ ≤ r) : ∃ a : D → D → unitary (Algebra M), …Mentions: OAI.KadisonKastler.Algebra, OAI.KadisonKastler.traceTwoNorm, OAI.KadisonKastler.FiniteVectorTrace
- theorem
OAI.KadisonKastler.exists_concrete_measurable_diagonal_unitary_comparisonline 111Source documentation
In a separably acting finite factor the diagonal comparison field is measurable after evaluation on every vector of the original Hilbert space.
theorem exists_concrete_measurable_diagonal_unitary_comparison {H : Type*} [NormedAddCommGroup H] [InnerProductSpace ℂ H] [CompleteSpace H] [SeparableSpace H] {M : VonNeumannAlgebra H} (hM : Generator.IsII1Factor M.toStarSubalgebra) {G D : Type*} [Group G] [Countable G] [MeasurableSpace D] {μ : Measure (D × D)} (shift : G → D → D) (W : G → D → unitary (Algebra M)) (hW : ∀ g t x, (W (g * t) x : Algebra M) = (W g x : Algebra M) * (W t (shift g x) : Algebra M)) (hWmeas : ∀ t, AEStronglyMeasurable (fun p : D × D => concreteTraceEmbedding hM ((W t p.1 : Algebra M) * star (W t p.2 : Algebra M))) μ) {r : ℝ} (hr0 : 0 ≤ r) (hr : r < 1) (hnear : ∀ t x y, ‖(W t x : Algebra M) * star (W t y : Algebra M) - 1‖ ≤ r) : …Mentions: OAI.Generator.IsII1Factor, OAI.KadisonKastler.Algebra, OAI.KadisonKastler.concreteTraceEmbedding