Definition
In mathematics, a topos is a category that behaves like the category of sheaves of sets on a topological space. 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.
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2-functor2-group2-ring3-categoryAbelian categoryAdditive categoryAdjoint functorAdjoint functorsAlexander GrothendieckAlgebraic categoryAlgebraic geometryAlgebraic stackAlgebraic structureAmerican EnglishAnabelian geometryAxiom of choiceAxiom of reducibilityAxiomatic systemBarry MazurBicategoryBritish EnglishCartesian closed categoryCategorificationCategory (mathematics)Category of abelian groupsCategory of groupsCategory of magmasCategory of modulesCategory of relationsCategory of ringsCategory of setsCategory theoryCharles Wells (mathematician)Classifying toposCoequalizerCoherent sheafCokernelColimitColin McLartyComma categoryCommutative diagramComplete categoryConcrete categoryCone (category theory)Conservative functorConstructive set theoryContravariant functorCoproductCrystal (mathematics)Dependent typeDerived functorDescriptive set theoryDeterminacyDiagonal functorDiagram (category theory)Direct limitEn-ringEnd (category theory)Enriched categoryEpimorphismEqualiser (mathematics)Equivalence of categoriesEquivalence relationEquivalent categoriesEric FriedlanderEssentially surjective functorExact functorExponential objectF. William LawvereFiber productFirst-order logicFlat topologyForgetful functorFormal systemFoundation of mathematicsFoundations of mathematicsFrames and localesFree categoryFull and faithful functorsFunction (mathematics)FunctorFunctor categoryGeneralized spaceGenerator (category theory)Geometric logicGeometrically unibranchGirard's paradoxGiraud's theoremGlossary of category theoryGrothendieckGrothendieck siteGroup (mathematics)Group actionGroup action (mathematics)GroupoidHigher-dimensional algebraHigher category theoryHilbert systemHistory of topos theoryHistory of type theoryHomomorphismHomotopyHomotopy categoryHomotopy hypothesisHomotopy type theoryIeke MoerdijkImage (mathematics)Initial and terminal objectsIntuitionistic type theoryInverse limitInverse systemIsomorphismIsomorphism of categoriesJean-Louis VerdierJean Giraud (mathematician)John BaezJohn Lane BellKan extensionKernel (category theory)Kleisli categoryLaw of excluded middleLeft adjointLimit (category theory)List of category theory topicsList of mathematical logic topicsList of set theory topicsLocalization of a categoryLuc IllusieM. Cristina PedicchioMathematical constructivismMathematical inductionMathematical logicMathematical proofMathematicsMichael ArtinMichael Barr (mathematician)Modal logicModel categoryModel theoryModule (mathematics)Monoidal categoryMonoidal functorMonomorphismMorphismMultidigraphN-group (category theory)N-monoidNaive set theoryNatural deductionNatural transformationNisnevich topologyNoetherian schemeOlivia CaramelloOpposite categoryOutline of category theoryOvercategoryPathological (mathematics)Peano axiomsPeter Johnstone (mathematician)Pierre DelignePointed setPowersetPre-abelian categoryPreadditive categoryPreorderPresheaf (category theory)Princeton University PressPro-finitePro-simplicial setProduct (category theory)Product categoryPseudo-functorPullback (category theory)Pushout (category theory)Quasi-categoryQuasitoposQuotient categoryRegular categoryRepresentable functorRing objectRinged spaceRinged toposRobert GoldblattRussell's paradoxSaunders Mac LaneScheme (mathematics)Second-order logicSeparable field extensionSet (mathematics)Set theorySheaf (mathematics)Simplex categorySite (mathematics)Smooth functorSpringer-VerlagStack (mathematics)Stephen SchanuelSteve Vickers (computer scientist)Strict 2-categoryStrict n-categoryString diagramStructuralism (philosophy of mathematics)SubalgebraSubcategorySubgroupSubobject classifierSubsetSymmetric monoidal categoryTetracategoryTopological spaceTopos (disambiguation)Traced monoidal categoryTricategoryType theoryUnivalent foundationsUniversal algebraUniversal constructionUniversal propertyWeak n-categoryYoneda LemmaYoneda lemmaZermelo set theoryZermelo–Fraenkel set theoryZero morphismÉtale fundamental groupÉtale homotopy theoryÉtale morphismÉtale topologyÉtale topos∞-groupoid∞-topos
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