Exact sequence in an abelian category
= Exact sequence in an abelian category
A sequence is exact at an object when the image of the incoming morphism equals the kernel of the outgoing morphism. It is exact when this holds everywhere.
= Exact sequence in an abelian category
A sequence is exact at an object when the image of the incoming morphism equals the kernel of the outgoing morphism. It is exact when this holds everywhere.