Extension groups between atoms in abelian categories
Abstract
We introduce the extension groups between atoms in an abelian category. For a locally noetherian Grothendieck category, the localizing subcategories closed under injective envelopes are characterized in terms of those extension groups. We also introduce the virtual duals of the extension groups between atoms to measure the global dimension of the category. A new topological property of atom spectra is revealed and it is used to relate the projective dimensions of atoms with the Krull-Gabriel dimensions. As a byproduct of the topological observation, we show that there exists a spectral space that is not homeomorphic to the atom spectrum of any abelian category.
- Publication:
-
arXiv e-prints
- Pub Date:
- October 2018
- DOI:
- 10.48550/arXiv.1810.04306
- arXiv:
- arXiv:1810.04306
- Bibcode:
- 2018arXiv181004306K
- Keywords:
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- Mathematics - Category Theory;
- Mathematics - Rings and Algebras;
- Mathematics - Representation Theory;
- 18E15 (Primary);
- 16D90;
- 16P40;
- 16G30 (Secondary)
- E-Print:
- 31 pages