OAI/Analysis/KadisonKastler/RelativePositiveDecomposition.lean

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Positive decomposition inside a finite-matrix central space

Orthogonal positive parts of a central vector remain central: the positive central projection cannot discard a common nonzero component of those parts. Their support projections therefore belong to the relative commutant.

  1. theorem OAI.KadisonKastler.positiveCone_parts_mem_centralVectorSpace line 26
  2. theorem OAI.KadisonKastler.exists_relative_positive_decomposition line 76
  3. theorem OAI.KadisonKastler.vectorSupportProjection_mem_relative line 98

    Source documentation

    The support of a matrix-central vector lies in the relative commutant.

    theorem vectorSupportProjection_mem_relative
        (E : MatrixUnitSystem ι (Algebra M))
        (J : H ≃ₗᵢ⋆[ℂ] H)
        (hright : ∀ a : Algebra M, conjugationOperator J a.val ∈ M.commutant)
        (α : H) (hα : α ∈ centralVectorSpace (matrixUnitConcreteAlgebra E) J) :
        (vectorSupportProjection M α).val.val ∈ E.relativeVonNeumann := by
    …

    Mentions: OAI.KadisonKastler.Algebra, OAI.KadisonKastler.conjugationOperator, OAI.KadisonKastler.centralVectorSpace, OAI.KadisonKastler.matrixUnitConcreteAlgebra, OAI.KadisonKastler.vectorSupportProjection