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Elke Enning

David Kerr: Dynamical alternating groups and the McDuff property. Oberseminar C*-Algebren.

Tuesday, 08.10.2024 16:15 im Raum SRZ 216/217

Mathematik und Informatik

In operator algebra theory central sequences have long played a significant role in addressing problems in and around amenability, having been used both as a mechanism for producing various examples beyond the amenable horizon and as a point of leverage for teasing out the finer structure of amenable operator algebras themselves. One of the key themes on the von Neumann algebra side has been the McDuff property for II_1 factors, which asks for the existence of noncommuting central sequences and is equivalent, by a theorem of McDuff, to tensorial absorption of the unique hyperfinite II_1 factor. We will show that, for a topologically free minimal action of a countable amenable group on the Cantor set, the von Neumann algebra of the associated dynamical alternating group is McDuff. This yields the first examples of simple finitely generated nonamenable groups for which the von Neumann algebra is McDuff. This is joint work with Spyros Petrakos.



Angelegt am 07.10.2024 von Elke Enning
Geändert am 07.10.2024 von Elke Enning
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