##### Department of Mathematics,

University of California San Diego

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### Operator Algebras Seminar

## Yusuke Isono

#### RIMS (Kyoto) and UCLA

## Bi-exact groups, strongly ergodic actions and group measure space type III factors with no central sequence

##### Abstract:

We investigate the asymptotic structure of (possibly type III) crossed product von Neumann algebras arising from arbitrary actions of bi-exact discrete groups (e.g. free groups) on amenable von Neumann algebras. We particularly prove a spectral gap rigidity result for the crossed products and, using recent results of Boutonnet-Ioana-Salehi Golsefidy, we provide the first example of group measure space type III factors with no central sequences. This is joint work with C. Houdayer.

Host: Adrian Ioana

### November 5, 2015

### 9:00 AM

### AP&M 7321

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