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arXiv · 0909.5639

On spectral gap rigidity and Connes invariant $χ(M)$

Sorin Popa
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Abstract

We calculate Connes' invariant $χ(M)$ for certain II$_1$ factors $M$ that can be obtained as inductive limits of subfactors with spectral gap, then use this to answer a question he posed in 1975, on the structure of McDuff factors $M$ with $χ(M)=1$.

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Sorin Popa. 2009-10-13. On spectral gap rigidity and Connes invariant $χ(M)$. https://arxiv.org/abs/0909.5639

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