EXT-GROUPS, DOLD k-INVARIANT AND FORMALITY Contents Introduction 1
Acknowledgments 2 1. Postnikov tower and k-invariant 2 1.1. P Page 1 EXT-GROUPS, DOLD …

Abstract In [16], a theory of universal extensions in abelian categories is developed; in
particular, the notion of Ext 1-universal object is presented. In the present paper, we show …

There are well-known identities involving the Ext bifunctor, coproducts, and products in AB4
abelian categories with enough projectives. Namely, for every such category\[\mathcal {A}\] …

Extended d-homology Page 709 ITALIAN JOURNAL OF PURE AND APPLIED
MATHEMATICS–N. 38–2017 (697–706) 697 EXTENDED d-HOMOLOGY SN Hosseini …

In this chapter we introduce the derived category of an abelian category, and more generally
the derived category of an exact category. For instance, we see that derived categories …

Assume that abelian categories $ A, B $ over a field admit countable direct limits and that
these limits are exact. Let $ F: D^+ _ {dg}(A)--> D^+ _ {dg}(B) $ be a DG quasi-functor such …

Let $\Sigma $ be a small category and $\mathcal {A} $ be a $\Sigma $-co-complete (resp.
$\Sigma $-complete) abelian category. It is a well-known fact that the category …

LOCALIZATION, ISOMORPHISMS AND ADJOINT ISOMORPHISM IN THE CATEGORY OF
MODULES Page 1 LOCALIZATION, ISOMORPHISMS AND ADJOINT ISOMORPHISM IN THE …

The fiber of functors between categories of algebras - ScienceDirect Skip to main contentSkip
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It is known that, for $ C $ an abelian category and $ I $ small, the functor category $ C^ I $ is
again abelian; thus we can do homology in such categories, and examine how it relates to …