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arXiv · 2507.04526

On the theories classified by an \'etendue

Joshua Wrigley
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Abstract

We give a model-theoretic characterisation of the geometric theories classified by \'etendues -- the `locally localic' topoi. They are the theories where each model is determined, syntactically and semantically, by any witness of a fixed collection of formulae.

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Joshua Wrigley. 2025-07-06. On the theories classified by an \'etendue. https://doi.org/10.1112/blms.70430

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