##### Department of Mathematics,

University of California San Diego

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### Math 243: Functional Analysis Seminar

## Pieter Spaas

#### UCLA

## What can central sequences in von Neumann algebras look like?

##### Abstract:

We will discuss central sequence algebras of von Neumann algebras, and provide a class of II$_1$ factors whose central sequence algebra is not the ``tail'' algebra associated to any decreasing sequence of von Neumann subalgebras. This settles a question of McDuff from 1969. We will also discuss an application of these techniques to the notion of tracial stability for groups. This is based on joint work with Adrian Ioana.

Host: Adrian Ioana

### January 28, 2020

### 10:00 AM

### AP&M 6402

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