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Elementary axioms for canonical points of toposes
Published online by Cambridge University Press: 12 March 2014
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Two elementary extensions of the topos axioms are given, each implying the topos has a local geometric morphism to a category of sets. The stronger one realizes sets as precisely the decidables of the topos, so there is a simple internal description of the range of validity of the law of excluded middle in the topos. It also has a natural geometric meaning. Models of the extensions in Grothendieck toposes are described.
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- Copyright © Association for Symbolic Logic 1987
References
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