Non-classification of free Araki-Woods factors and τ-invariants

Román Sasyk, Asger Törnquist, Stefaan Vaes

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Abstract

We define the standard Borel space of free Araki-Woods factors and prove that their isomorphism relation is not classifiable by countable structures. We also prove that equality of τ-topologies, arising as invariants of type III factors, as well as cocycle and outer conjugacy of actions of abelian groups on free product factors are not classifiable by countable structures.

Original languageEnglish
JournalGroups, Geometry, and Dynamics
Volume13
Issue number4
Pages (from-to)1219-1234
ISSN1661-7207
DOIs
Publication statusPublished - 2019

Keywords

  • Classification of factors and their automorphisms
  • Descriptive set theory
  • Fourier analysis on locally compact abelian groups
  • Von Neumann algebras

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