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RELATIVELY AMENABLE ACTIONS OF THOMPSON’S GROUPS

Part of: Selfadjoint operator algebras Abstract harmonic analysis

Published online by Cambridge University Press:  03 November 2021

EDUARDO SCARPARO Open the ORCID record for EDUARDO SCARPARO [Opens in a new window]
EDUARDO SCARPARO*
Affiliation:
Department of Mathematics, Federal University of Santa Catarina, Florianópolis, Santa Catarina 88040-900, Brazil
*
e-mail: [email protected]
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Abstract

We investigate the notion of relatively amenable topological action and show that the action of Thompson’s group T on $S^1$ is relatively amenable with respect to Thompson’s group F. We use this to conclude that F is exact if and only if T is exact. Moreover, we prove that the groupoid of germs of the action of T on $S^1$ is Borel amenable.

Keywords

relatively amenable actionsThompson’s groupsKirchberg algebrauniversal coefficient theoremgroupoid of germs

MSC classification

Primary: 43A07: Means on groups, semigroups, etc.; amenable groups
Secondary: 46L05: General theory of $C^*$-algebras
Type
Research Article
Information
Bulletin of the Australian Mathematical Society , Volume 106 , Issue 1 , August 2022 , pp. 144 - 150
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Copyright
© The Author(s), 2021. Published by Cambridge University Press on behalf of Australian Mathematical Publishing Association Inc.

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