| Time: | 12:30 - 13:30 |
| Room: |
Wean Hall 8220
|
| Speaker: |
Clinton Conley Department of Mathematical Sciences CMU |
| Title: |
Amenability and μ-hyperfiniteness
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| Abstract: | Ornstein-Weiss showed in the early 80s that any measure-preserving Borel action of a countable amenable group on a standard probability space generates, after deleting a null set, a hyperfinite orbit equivalence relation. This was soon generalized by Connes-Feldman-Weiss to handle non-measure-preserving actions. After some background on amenability, we discuss a modern graph-theoretic approach to proving these theorems, building on work of Elek, Kaimanovich, and Kechris-Miller. This talk includes joint work with Gaboriau, Marks, and Tucker-Drob. |