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Topos theory


In mathematics, a topos (UK /ˈtɒpɒs/, US /ˈtps, ˈtpɒs/; plural topoi /ˈtpɔɪ/ or /ˈtɒpɔɪ/, or toposes) is a category that behaves like the category of sheaves of sets on a topological space (or more generally: on a site). Topoi behave much like the category of sets and possess a notion of localization; they are in a sense a generalization of point-set topology. The Grothendieck topoi find applications in algebraic geometry; the more general elementary topoi are used in logic.


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Wikipedia

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