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arXiv · 0811.1084

The planar algebra of diagonal subfactors

Dietmar Bisch·Paramita Das·Shamindra Kumar Ghosh
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Abstract

There is a natural construction which associates to a finitely generated, countable, discrete group $G$ and a 3-cocycle $ω$ of $G$ an inclusion of II$_1$ factors, the so-called diagonal subfactors (with cocycle). In the case when the cocycle is trivial these subfactors are well studied and their standard invariant (or planar algebra) is known. We give a description of the planar algebra of these subfactors when a cocycle is present. The action of Jones' planar operad involves the 3-cocycle $ω$ explicitly and some interesting identities for 3-cocycles appear when naturality of the action is verified.

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Dietmar Bisch, Paramita Das, Shamindra Kumar Ghosh. 2008-12-29. The planar algebra of diagonal subfactors. https://arxiv.org/abs/0811.1084

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