How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
Abelian category
Definition
An abelian category is an additive category (Additive category) in which every morphism has a kernel and a cokernel, and in which for every morphism the canonical comparison morphism
constructed in The canonical morphism from the coimage to the image exists and is unique is an isomorphism.
The first two clauses are Grothendieck's AB1, while the invertibility of the canonical map is this page's working form of AB2.
Depends on
Used by
- An abelian category that is a preorder is trivial Corollary
- Composition of Deligne kernels is balanced tensor product Corollary
- Finite one-sided exactness is equivalent to the existence of the corresponding adjoint Corollary
- In an abelian category, monic means zero kernel and epic means zero cokernel Corollary
- The center is Morita invariant, via natural endomorphisms of the identity Corollary
- The kernel-cokernel sequence of a composite is a snake Corollary
- An exact functor need not be faithful Counterexample
- Filtered vector spaces can be additive with kernels and cokernels without being abelian Counterexample
- Topological abelian groups are additive but not abelian Counterexample
- Torsion-free abelian groups do not form an abelian category Counterexample
- Abelian subcategory and exact embedding Definition
- Cartan-Eilenberg injective resolution of a bounded-below complex Definition
- Chain complex in an abelian category Definition
- Cochain complex in an abelian category Definition
- Cohomological functor on a triangulated category Definition
- Exact couple Definition
- Graded Grothendieck groups, shift action, and Cartan map Definition
- Grothendieck group of an essentially small abelian category Definition
- Homological functor on a triangulated category Definition
- Homological spectral sequence Definition
- Increasing and decreasing filtration of an object Definition
- Injective object Definition
- Left and right Nakayama functors by finite kernel calculus Definition
- Locally finite k-linear abelian categories Definition
- Projective object Definition
- Semisimple objects and semisimple abelian categories Definition
- Small projective generators and progenerators Definition
- Superfluous subobjects and projective covers in an abelian category Definition
- Supplied injective resolution data Definition
- Supplied projective resolution data Definition
- The arrow category of an abelian category Definition
- The Deligne product of finite linear categories Definition
- A nonsplit simple has Hom-pairing diagonal two Example
- The Deligne product of finite vector spaces is finite vector spaces Example
- FALSE: every abelian category has a generator False statement
- Abelian-group model for spectral-sequence computations Lemma
- Bilinear right exact functors are determined by their value on the regular modules Lemma
- Colimits of a graded additive functor equal right exactness plus coproduct preservation Lemma
- Degreewise direct sums and homogeneous free covers in graded modules Lemma
- Finite biproducts of injective objects are injective Lemma
…and 57 more results.
Dependency tree · two levels
9 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- Alexandre Grothendieck, Some aspects of homological algebra, §1.4 (standard reference, not scraped)
- The Stacks Project, Section 12.5, Definition 12.5.1 (standard reference, not scraped)
- Gautam Tamme, Algebra II Lecture 9, §9.4 (standard reference, not scraped)