Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
4591934 | Journal of Functional Analysis | 2010 | 15 Pages |
Abstract
Using Baire category techniques we prove that Araki–Woods factors are not classifiable by countable structures. As a result, we obtain a far reaching strengthening as well as a new proof of the well-known theorem of Woods that the isomorphism problem for ITPFI factors is not smooth. We derive as a consequence that the odometer actions of Z that preserve the measure class of a finite non-atomic product measure are not classifiable up to orbit equivalence by countable structures.
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