Positive Sofic Entropy Implies Finite Stabilizer

We prove that, for a measure preserving action of a sofic group with positive sofic entropy, the stabilizer is finite on a set of positive measures. This extends the results of Weiss and Seward for amenable groups and free groups, respectively. It follows that the action of a sofic group on its subg...

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Bibliographic Details
Main Author: Tom Meyerovitch
Format: Article
Language:English
Published: MDPI AG 2016-07-01
Series:Entropy
Subjects:
Online Access:http://www.mdpi.com/1099-4300/18/7/263
Description
Summary:We prove that, for a measure preserving action of a sofic group with positive sofic entropy, the stabilizer is finite on a set of positive measures. This extends the results of Weiss and Seward for amenable groups and free groups, respectively. It follows that the action of a sofic group on its subgroups by inner automorphisms has zero topological sofic entropy, and that a faithful action that has completely positive sofic entropy must be free.
ISSN:1099-4300