Classification of actions of discrete Kac algebras on injective factors

Toshihiko Masuda, Reiji Tomatsu

Research output: Contribution to journalReview articlepeer-review

6 Citations (Scopus)


We will study two kinds of actions of a discrete amenable Kac algebra. The first one is an action whose modular part is normal. We will construct a new invariant which generalizes a characteristic invariant for a discrete group action, and we will present a complete classification. The second is a centrally free action. By constructing a Rohlin tower in an asymptotic centralizer, we will show that the Connes-Takesaki module is a complete invariant.

Original languageEnglish
Pages (from-to)1-134
Number of pages134
JournalMemoirs of the American Mathematical Society
Issue number1160
Publication statusPublished - 2017 Jan
Externally publishedYes


  • Action
  • Discrete Kac algebra
  • Von Neumann algebra

ASJC Scopus subject areas

  • Mathematics(all)
  • Applied Mathematics


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