Proceedings of the American Mathematical Society

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ISSN 1088-6826(e) ISSN 0002-9939(p)

On spectral gap rigidity and Connes invariant $\chi (M)$

Author(s): Sorin Popa
Journal: Proc. Amer. Math. Soc. 138 (2010), 3531-3539.
MSC (2000): Primary 46L10, 46L37, 46L40
Posted: June 15, 2010
MathSciNet review: 2661553
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Abstract: We calculate Connes' invariant $\chi (M)$ for certain II $_{1}$ factors that can be obtained as inductive limits of subfactors with spectral gap. Then we use this to answer a question he posed in 1975 on the structure of McDuff factors with $\chi (M)=1$ .

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