English

Outer Actions of a Discrete Amenable Group on Approximately Finite Dimensional Factors III, The Type $\text{III}_\lambda$ Case, $\pmb{0<\lambda<1}$, Examples

Operator Algebras 2009-03-24 v1

Abstract

In this last article of the series on outer actions of a countable dicrete amenable group on AFD factors, we analyze outer actions of a countable discrete free abelian group on an AFD factor of type IIIλ\text{III}_\lambda, 0<λ<10<\lambda< 1, and compute outer conjugacy invariants. As a byproduct, we discover the asymmetrization technique for coboundary condition on a T\Bbb T-valued cocycle of a torsion free abelian group, which might have been known by the group cohomologists. As the asymmetrization technique gives us a very handy criteria for coboundaries, we present it here in detail in the second section.

Keywords

Cite

@article{arxiv.0903.3673,
  title  = {Outer Actions of a Discrete Amenable Group on Approximately Finite Dimensional Factors III, The Type $\text{III}_\lambda$ Case, $\pmb{0<\lambda<1}$, Examples},
  author = {Yoshikazu Katayama and Masamichi Takesaki},
  journal= {arXiv preprint arXiv:0903.3673},
  year   = {2009}
}

Comments

78pages

R2 v1 2026-06-21T12:42:59.647Z