English

Boundary actions of outer automorphism groups of Thompson-like groups

Group Theory 2025-12-17 v1 Dynamical Systems Operator Algebras

Abstract

For every Cuntz--Krieger groupoid, we show that there is a topologically free boundary action of the outer automorphism group of its topological full group on the Hilbert cube. In particular, these outer automorphism groups, including the outer automorphism groups of all Higman--Thompson groups, are C*-simple.

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Cite

@article{arxiv.2512.14324,
  title  = {Boundary actions of outer automorphism groups of Thompson-like groups},
  author = {Chris Bruce and Xin Li and Takuya Takeishi},
  journal= {arXiv preprint arXiv:2512.14324},
  year   = {2025}
}

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34 pages