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The following outline is provided as an overview of and guide to category theory:

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Essence of category theory

  • Category
  • Functor
  • Natural transformation

Branches of category theory

  • Homological algebra
  • Diagram chasing
  • Topos theory
  • Enriched category theory
  • Higher category theory
  • Categorical logic
  • Applied category theory

Specific categories

  • Category of sets
  • Concrete category
  • Category of small categories
  • Category of vector spaces
  • Category of graded vector spaces
  • Category of chain complexes
  • Category of finite dimensional Hilbert spaces
  • Category of sets and relations
  • Category of topological spaces
  • Category of metric spaces
  • Category of preordered sets
  • Category of groups
  • Category of abelian groups
  • Category of rings
  • Category of magmas

Objects

  • Initial object
  • Terminal object
  • Zero object
  • Subobject
  • Group object
  • Magma object
  • Natural number object
  • Exponential object

Morphisms

  • Epimorphism
  • Monomorphism
  • Zero morphism
  • Normal morphism
  • Dual (category theory)
  • Groupoid
  • Image (category theory)
  • Coimage
  • Commutative diagram
  • Cartesian morphism
  • Slice category

Functors

  • Isomorphism of categories
  • Natural transformation
  • Equivalence of categories
  • Subcategory
  • Faithful functor
  • Full functor
  • Forgetful functor
  • Representable functor
  • Functor category
  • Adjoint functors
  • Galois connection
  • Pontryagin duality
  • Affine scheme
  • Monad (category theory)
  • Comonad
  • Combinatorial species
  • Exact functor
  • Derived functor
  • Dominant functor
  • Enriched functor
  • Kan extension of a functor
  • Hom functor
  • Yoneda lemma

Limits

  • Product (category theory)
  • Equaliser (mathematics)
  • Kernel (category theory)
  • Pullback (category theory)/fiber product
  • Inverse limit
  • Pro-finite group
  • Colimit
  • Coproduct
  • Coequalizer
  • Cokernel
  • Pushout (category theory)
  • Direct limit
  • Biproduct
  • Direct sum

Additive structure

  • Preadditive category
  • Additive category
  • Pre-Abelian category
  • Abelian category
  • Exact sequence
  • Exact functor
  • Snake lemma
  • Nine lemma
  • Five lemma
  • Short five lemma
  • Mitchell's embedding theorem
  • Injective cogenerator
  • Derived category
  • Triangulated category
  • Model category
  • 2-category

Dagger categories

  • Dagger symmetric monoidal category
  • Dagger compact category
  • Strongly ribbon category

Monoidal categories

  • Closed monoidal category
  • Braided monoidal category
  • Symmetric monoidal category

Structure

  • Semigroupoid
  • Comma category
  • Localization of a category
  • Enriched category
  • Bicategory

Topoi, toposes

  • Sheaf
  • Gluing axiom
  • Descent (category theory)
  • Grothendieck topology
  • Introduction to topos theory
  • Subobject classifier
  • Pointless topology
  • Heyting algebra

History of category theory

  • History of category theory

Persons influential in the field of category theory

Category theory scholars

  • Saunders Mac Lane
  • Samuel Eilenberg
  • Max Kelly
  • William Lawvere
  • AndrĂ© Joyal

See also

  • Abstract nonsense
  • Glossary of category theory