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arXiv · 1803.02336

A symmetric $\beta$-model

Stephen G. Simpson
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Abstract

We prove that there exists a countable $\beta$-model in which, for all reals $X$ and $Y$, $X$ is definable from $Y$ if and only $X$ is hyperarithmetical in $Y$. We also obtain some related results and pose some related questions.

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Stephen G. Simpson. 2018-03-06. A symmetric $\beta$-model. https://arxiv.org/abs/1803.02336

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