Group actions on von Neumann algebras with compact open subgroups

Takumi Nishihara

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arXiv · 2608.27827

Group actions on von Neumann algebras with compact open subgroups

Takumi Nishihara

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Abstract

We study strictly outer actions of locally compact groups with a compact open subgroup on von Neumann factors. For amenable groups, we prove 2-cohomology vanishing and obtain classification results using a description of the central sequence algebra and Rohlin-type observations. We also characterize the inclusions of factors associated with group actions, and extend M. Choda's result to this locally compact setting.

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Takumi Nishihara. 2026-08-28. Group actions on von Neumann algebras with compact open subgroups. https://arxiv.org/abs/2608.27827

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