Ryoya Arimoto

activity

20222026

collaborators

5 papers

math.OA2026

$C^{*}$ -selflessness of groups of homeomorphisms

Ryoya Arimoto

We prove that $C^{*}$ -simple groups which admit a faithful extreme boundary are $C^{*}$ -selfless. More precisely, we establish complete selflessness of the canonical…

math.DS2025

Non-strong ergodicity of canonical actions of the Thompson groups

Ryoya Arimoto

We show that the canonical actions of the Thompson group V and its generalizations on the Cantor set are not strongly ergodic. This implies that the associated crossed product von…

math.OA2025

Topological full groups arising from Cuntz and Cuntz-Toeplitz algebras and their crossed products

Ryoya Arimoto, Taro Sogabe

In this paper, we investigate the topological full groups arising from the Cuntz and Cuntz-Toeplitz algebras and their crossed products with the Cartan subalgebras of Cuntz and Cun…

math.OA2023

Simplicity of crossed products of the actions of totally disconnected locally compact groups on their boundaries

Ryoya Arimoto

We prove that if a totally disconnected locally compact group admits a topologically free boundary, then the reduced crossed product of continuous functions on its Furstenberg boun…

math.GR2022

On the type of the von Neumann algebra of an open subgroup of the Neretin group

Ryoya Arimoto

The Neretin group $N_{d, k}$ is the totally disconnected locally compact group consisting of almost automorphisms of the tree $T_{d, k}$ . This group has a disting…

C∗-selflessness of groups of homeomorphisms

Non-strong ergodicity of canonical actions of the Thompson groups

Topological full groups arising from Cuntz and Cuntz-Toeplitz algebras and their crossed products

Simplicity of crossed products of the actions of totally disconnected locally compact groups on their boundaries

On the type of the von Neumann algebra of an open subgroup of the Neretin group

$C^{*}$ -selflessness of groups of homeomorphisms