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Examples of subfactors with property T standard invariant

Dietmar Bisch·Sorin Popa
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Abstract

Let H and K be two finite groups with a properly outer action on the II_1 factor M. We prove that the group type inclusions $M^H \subset M \rtimes K$, studied earlier by Bisch and Haagerup, have property T in the sense of Popa if and only if the group generated by H and K in the outer automorphism group of M has Kazhdan's property T. This construction yields irreducible, infinite depth subfactors with small Jones indices and property T standard invariant.

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Dietmar Bisch, Sorin Popa. 1998-04-09. Examples of subfactors with property T standard invariant. https://arxiv.org/abs/math/9804056

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