Coserreness with respect to specialization closed subsets and some Serre subcategories
Abstract
Let 𝒵 be a specialization closed subset of SpecR and 𝒮 be a Serre subcategory of ModR. As a generalization of the notion of cofiniteness, we introduce the concept of 𝒵-coserreness with respect to 𝒮 (see Definition 4.1). First, as a main result, for some special Serre subcategories 𝒮, we show that an R-module M with dimRM≤1 is 𝒵-coserre with respect to 𝒮 if and only if Ext0,1R(R/𝔞,M)∈𝒮 for all ideals 𝔞∈F(𝒵). Indeed, this result provides a partial answer to a question that was recently raised in [K. Bahmanpour, R. Naghipour and M. Sedghi, Modules cofinite and weakly cofinite with respect to an ideal, J. Algebra Appl. 16 (2018) 1–17]. As an application of this result, we show that the category of 𝒵-coserre R-modules M with dimRM≤1 is a full Abelian subcategory of ModR. Also, for every homologically bounded R-complex X whose homology modules belong to 𝒮 we show that the local cohomology modules Hi𝒵(X) for all i, are 𝒵-coserre in all the cases where dimR𝒵≤1, dimRX≤2−supX and cd(𝒵,X)≤1−supX.
Communicated by D. Herbera