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topos
EntityQ2143621· pop 14· linked from 284 articles

Also known as topoi, toposes, elementary topos

In mathematics, a topos (, ; plural topoi or , 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. The Grothendieck topoi find applications in algebraic geometry, and more general elementary topoi are used in logic.

~21 min read

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21 sections
Contents
  • Grothendieck topos (topos in geometry)
  • Equivalent definitions
  • Giraud's axioms
  • Examples
  • Category of sets and G-sets
  • Topoi from ringed spaces
  • Pathologies
  • Geometric morphisms
  • Points of topoi
  • Essential geometric morphisms
  • Ringed topoi
  • Homotopy theory of topoi
  • Elementary topoi (topoi in logic)
  • Introduction
  • Formal definition
  • Logical functors
  • Explanation
  • Further examples and non-examples
  • See also
  • Notes
  • References

In mathematics, a topos (, ; plural topoi or , 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. The Grothendieck topoi find applications in algebraic geometry, and more general elementary topoi are used in logic.

The mathematical field that studies topoi is called topos theory.

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