Article ID Journal Published Year Pages File Type
4591934 Journal of Functional Analysis 2010 15 Pages PDF
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.

Related Topics
Physical Sciences and Engineering Mathematics Algebra and Number Theory