Special Cases
- A pre-abelian category is an additive category in which every morphism has a kernel and a cokernel.
- An abelian category is a pre-abelian category such that every monomorphism and epimorphism is normal.
The additive categories most commonly studied are in fact abelian categories; for example, Ab is an abelian category.
Read more about this topic: Additive Category
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