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arXiv · 2002.02614

Oracle computability of conditional expectations onto subfactors

Isaac Goldbring
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Abstract

We initiate the effective study of conditional expectations onto subfactors. Our main result is that if $M$ is an existentially closed II$_1$ factor with a w-spectral gap subfactor $N$, then the conditional expectation function onto $N$ can be computed from a (Turing) oracle that computes a presentation of $M$, the inclusion of $N$ into $M$, and a spectral gap function for the pair $(M,N)$.

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Isaac Goldbring. 2020-02-07. Oracle computability of conditional expectations onto subfactors. https://arxiv.org/abs/2002.02614

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