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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 a number of constructions throughout mathematics.
In mathematics, certain functors may be derived to obtain other functors closely related to the original ones. This operation, while fairly abstract, unifies...
using the functor G(A)=HomR(A,B). For a fixed module B, this is a contravariant left exact functor, and thus we also have right derivedfunctors RnG, and...
introduced to refine and in a certain sense to simplify the theory of derivedfunctors defined on A. The construction proceeds on the basis that the objects...
In mathematics, the Ext functors are the derivedfunctors of the Hom functor. Along with the Tor functor, Ext is one of the core concepts of homological...
In mathematics, the direct image functor is a construction in sheaf theory that generalizes the global sections functor to the relative case. It is of fundamental...
mathematics, the Tor functors are the derivedfunctors of the tensor product of modules over a ring. Along with the Ext functor, Tor is one of the central...
the homotopy category (i.e., derived category). By definition, it is the left derivedfunctor of the tensor product functor − ⊗ A − : M A × A M → R M {\displaystyle...
derivedfunctor cohomology of an object and the homology of a chain complex since hypercohomology corresponds to the derived global sections functor R...
particularly homological algebra, an exact functor is a functor that preserves short exact sequences. Exact functors are convenient for algebraic calculations...
{F}})} in the derived category of sheaves on S', similarly as mentioned above. Here L g ∗ {\displaystyle Lg^{*}} is the (total) derivedfunctor of the pullback...
Combinatorial species Exact functorDerivedfunctor Dominant functor Enriched functor Kan extension of a functor Hom functor Product (category theory) Equaliser...
algebraic situations involving derivedfunctors. While their theoretical importance has decreased since the introduction of derived categories, they are still...
such as exact sequences, and especially short exact sequences, and derivedfunctors. Important theorems that apply in all abelian categories include the...
additional structure of a "translation functor" and a class of "exact triangles". Prominent examples are the derived category of an abelian category, as...
computes the derivedfunctors of the composition of two functors G ∘ F {\displaystyle G\circ F} , from knowledge of the derivedfunctors of F {\displaystyle...
{\displaystyle \operatorname {H} ^{i}(X,-)} as the i-th right derivedfunctor of the global section functor Γ ( X , − ) {\displaystyle \Gamma (X,-)} . Given a ringed...
exact but not necessarily right exact. We may therefore form its right derivedfunctors. Their values are abelian groups and they are denoted by H n ( G ,...
{\displaystyle G^{(2)},G^{(3)},\ldots } are called the second derived subgroup, third derived subgroup, and so forth, and the descending normal series ⋯...
total derivedfunctor theorem of Quillen says that the total left derivedfunctor LF: Ho(C) → Ho(D) is a left adjoint to the total right derivedfunctor RG:...
the groups Hi(X,E) for integers i are defined as the right derivedfunctors of the functor E ↦ E(X). This makes it automatic that Hi(X,E) is zero for...
adjoint functors, as does the unicity. The notation Rf! is an abuse of notation insofar as there is in general no functor f! whose derivedfunctor would...
functors from the derived category of sheaves on X to abelian groups. In a broad sense of the word, "cohomology" is often used for the right derived functors...
operations are six functors. Usually these are functors between derived categories and so are actually left and right derivedfunctors. the direct image...