Extension groups between atoms in abelian categories

JOURNAL OF PURE AND APPLIED ALGEBRA

卷:225

Article

Kanda, Ryo¹ 

[1] Osaka City Univ, Grad Sch Sci, Dept Math, 3-3-138 Sugimoto, Sumiyoshi, Osaka 5588585, Japan

关键词: Abelian category;    Grothendieck category;    Atom spectrum;    Ziegler spectrum;    Localizing subcategory;    Krull-Gabriel dimension;   

DOI  :  10.1016/j.jpaa.2021.106669

来源: Elsevier

【 摘 要 】

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. (C) 2021 Elsevier B.V. All rights reserved.

【 授权许可】

Free