• hom-sets (i.e. sets of morphisms between objects) give rise to important functors to the category of sets. These functors are called hom-functors and...
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  • the group homomorphism Hom(f, g): Hom(A2, B1) → Hom(A1, B2) is given by φ ↦ g ∘ φ ∘ f. See Hom functor. Representable functors We can generalize the previous...
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  • Yoneda lemma (redirect from Yoneda functor)
    a hom-functor. This functor is denoted: h A ( − ) ≡ H o m ( A , − ) {\displaystyle h_{A}(-)\equiv \mathrm {Hom} (A,-)} . The (covariant) hom-functor h...
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  • tensor-hom adjunction is that the tensor product − ⊗ X {\displaystyle -\otimes X} and hom-functor Hom ⁡ ( X , − ) {\displaystyle \operatorname {Hom} (X,-)}...
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  • from the fact the covariant Hom functor Hom(N, –) : C → Set preserves all limits in C. By duality, the contravariant Hom functor must take colimits to limits...
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  • category generated by it. Since Hom S ′ {\displaystyle \operatorname {Hom} _{S'}} is a functor, ( x , y ) ↦ Sing ⁡ | Hom C ⁡ ( x , y ) | {\displaystyle...
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  • In mathematics, the Ext functors are the derived functors of the Hom functor. Along with the Tor functor, Ext is one of the core concepts of homological...
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  • of sets. For each object A of C let Hom(A,–) be the hom functor that maps object X to the set Hom(A,X). A functor F : C → Set is said to be representable...
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  • {\displaystyle \mathrm {hom} _{\mathcal {C}}(Fd,c)} , φ f {\displaystyle \varphi f} is the right adjunct of f {\displaystyle f} (p. 81). The functor F {\displaystyle...
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  • category theory, a faithful functor is a functor that is injective on hom-sets, and a full functor is surjective on hom-sets. A functor that has both properties...
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  • Presheaf (category theory) (category Functors)
    the contravariant hom-functor Hom(–, A) for some object A of C is called a representable presheaf. Some authors refer to a functor F : C o p → V {\displaystyle...
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  • functor is called the internal Hom functor, and the object A ⇒ B {\displaystyle A\Rightarrow B} is called the internal Hom of A {\displaystyle A} and B...
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  • direct image functor, taking sheaves and their morphisms on the domain to sheaves and morphisms on the codomain, and an inverse image functor operating in...
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  • specifically in the area of category theory, a forgetful functor (also known as a stripping functor) "forgets" or drops some or all of the input's structure...
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  • internal hom [x, y]. Every closed category has a forgetful functor to the category of sets, which in particular takes the internal hom to the external hom. A...
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  • Thus the contravariant hom-functor changes coproducts into products. Stated another way, the hom-functor, viewed as a functor from the opposite category...
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  • In mathematics, certain functors may be derived to obtain other functors closely related to the original ones. This operation, while fairly abstract, unifies...
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  • {\displaystyle \mathrm {Hom} (A\otimes B,C)\cong \mathrm {Hom} (A,B\Rightarrow C).} Here, Hom denotes the (external) Hom-functor of all morphisms in the...
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  • {\displaystyle F:\mathrm {Hom} _{\mathbf {Vect} }(T,U)\rightarrow \mathrm {Hom} _{\mathbf {Vect} }(F(T),F(U)),} where Hom is notation for Hom functor. If this map...
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  • exact functors are the Hom functors: if A is an abelian category and A is an object of A, then FA(X) = HomA(A,X) defines a covariant left-exact functor from...
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  • Thumbnail for Category of relations
    to make Rel a dagger category. The category has two functors into itself given by the hom functor: A binary relation R ⊆ A × B and its transpose RT ⊆...
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  • category, enriched functor, etc... reduce to the original definitions from ordinary category theory. An enriched category with hom-objects from monoidal...
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  • 2-category (redirect from Lax functor)
    objects a and b the hom-set Hom ⁡ ( a , b ) {\displaystyle \operatorname {Hom} (a,b)} acquires a structure of a category as a functor category. A vertical...
    19 KB (2,524 words) - 10:33, 29 April 2025
  • in C, the natural functor (evaluation at the identity) Hom _ ( h x , F ) → F ( x ) {\displaystyle {\underline {\operatorname {Hom} }}(h_{x},F)\to F(x)}...
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  • a branch of mathematics, a functor category D C {\displaystyle D^{C}} is a category where the objects are the functors F : C → D {\displaystyle F:C\to...
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  • Loop space (redirect from Loop functor)
    computer science is currying, where the cartesian product is adjoint to the hom functor.) Informally this is referred to as Eckmann–Hilton duality. The loop...
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  • product and the Hom functor are adjoint; however, they might not always lift to an exact sequence. This leads to the definition of the Tor functor and the Ext...
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  • Thumbnail for Category theory
    we have ∘ : hom ( b , c ) × hom ( a , b ) ↦ hom ( a , c ) {\displaystyle \circ :{\text{hom}}(b,c)\times {\text{hom}}(a,b)\mapsto {\text{hom}}(a,c)} The...
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  • theory, monoidal functors are functors between monoidal categories which preserve the monoidal structure. More specifically, a monoidal functor between two...
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  • category, it is equivalent to require that the hom functor Hom C ⁡ ( − , Q ) {\displaystyle \operatorname {Hom} _{\mathbf {C} }(-,Q)} carries monomorphisms...
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