Dixmier traces as singular symmetric functionals and applications to measurable operators

By S. Lord, A. Sedaev, Fedor Sukochev. 2005

63 citations recorded by the source corpus.

Abstract We unify various constructions and contribute to the theory of singular symmetric functionals on Marcinkiewicz function/operator spaces. This affords a new approach to the non-normal Dixmier and Connes–Dixmier traces (introduced by Dixmier and adapted to non-commutative geometry by Connes) living on a general Marcinkiewicz space associated with an arbitrary semifinite von Neumann algebra. The corollaries to our approach, stated in terms of the operator ideal L ( 1 , ∞ ) (which is a special example of an operator Marcinkiewicz space), are: (i) a new characterization of the set of all positive measurable operators from L ( 1 , ∞ ) , i.e. those on which an arbitrary Connes–Dixmier trace yields the same value. In the special case, when the operator ideal L ( 1 , ∞ ) is considered on a type I infinite factor, a bounded operator x belongs to L ( 1 , ∞ ) if and only if the sequence of singular numbers { s n ( x ) } n ⩾ 1 (in the descending order and counting the multiplicities) satisfies ∥ x ∥ ( 1 , ∞ ) ≔ sup N ⩾ 1 1 Log ( 1 + N ) ∑ n = 1 N s n ( x ) ∞ . In this case, our characterization amounts to saying that a positive element x ∈ L ( 1 , ∞ ) is measurable if and only if lim N → ∞ 1 Log N ∑ n = 1 N s n ( x ) exists; (ii) the set of Dixmier traces and the set of Connes–Dixmier traces are norming sets (up to equivalence) for the space L ( 1 , ∞ ) / L 0 ( 1 ∞ ) , where the space L 0 ( 1 , ∞ ) is the closure of all finite rank operators in L ( 1 , ∞ ) in the norm ∥ . ∥ ( 1 , ∞ ) .

Subfields: Algebra and Number Theory, Applied Mathematics, Mathematical Physics

View Paper: https://www.semanticscholar.org/paper/11ec13f0dc4bf1c8b81f7728b5118b054f9058ca

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In Algebra and Number Theory

  1. Fedor Sukochev
  2. Alan L. Carey
  3. E. Semenov
  4. A. Rennie
  5. J. Phillips

In Applied Mathematics

  1. Fedor Sukochev
  2. Alan L. Carey
  3. E. Semenov

In Mathematical Physics

  1. Fedor Sukochev
  2. Alan L. Carey
  3. E. Semenov
  4. A. Rennie
  5. D. Potapov
  6. J. Phillips

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