Is it true that an additive functor between abelian categories commutes with colimits if it's right-exact and commutes with (arbitrary) direct sums?
If yes, does someone know a good source of a proof?
Is it true that an additive functor between abelian categories commutes with colimits if it's right-exact and commutes with (arbitrary) direct sums?
If yes, does someone know a good source of a proof?
In a category with coproducts and coequalizers, any colimit can be built out of coproducts and coequalizers. This is a nice exercise. In an $\text{Ab}$-enriched category, coequalizers can be replaced with cokernels. This is another nice exercise.