arXiv subjects

Takeshi Yoshizawa

Publications and source records attributed to Takeshi Yoshizawa.

7 recordsLinked to original sources

arXiv2024

Mutations of ordinary torsion theories and generalized torsion theories connected by a Serre subcategory

Understanding how torsion theories are described and constructed is crucial to the study of torsion theory. Mutations of torsion theories have been studied as a method of constructing another torsion theory from a given one. We have already obtained how to mutate ordinary torsion theories into generalized torsion theories associated with a Serre subcategory. The paper investigates when the generalized torsion theories give ordinary torsion theories and when ordinary torsion theories provide each other.

math.AC↗

arXiv2021

Annihilators of local cohomology modules via a classification theorem of the dominant resolving subcategories

This paper investigates when local cohomology modules have an annihilator that does not depend on the choice of an ideal. Takahashi classified the dominant resolving subcategories of the category of finitely generated modules over a commutative Noetherian ring. We show that his classification theorem describes annihilation results of local cohomology modules over a finite-dimensional ring with certain assumptions or a Cohen-Macaulay ring.

math.AC↗

arXiv2017

Melkersson conditions with respect to a prime ideal

Aghapournahr and Melkersson introduced the notion of Melkersson condition on a Serre subcategory of the module category over a commutative noetherian ring. This paper investigates the structure of set of prime ideals satisfying a Melkersson condition on a Serre subcategory. We try to calculate members of a set of these prime ideals for a subcategory consisting of extension modules in two given Serre subcategories of the module category. Meanwhile, we classify the structure of set of prime ideals satisfying a Melkersson condition over a 0-dimensional ring, a 1-dimensional local ring, and a 2-dimensional local domain.

math.AC↗

arXiv2011

Subcategories of extension modules by Serre subcategories

In this paper, we consider subcategories consisting of the extensions of modules in two given Serre subcategories to find a method of constructing Serre subcategories of the category of modules. We shall give a criterion for this subcategory to be a Serre subcategory.

math.AC↗

arXiv2010

An example of Melkersson subcategory which is not closed under injective hulls

The Melkersson subcategory is a special Serre subcategory. It was proved that a Serre subcategory which is closed under injective hulls is a Melkersson subcategory. However, it has been an open question whether the contrary implication holds. In this paper, we shall show that this question has a negative answer in general.

math.AC↗

arXiv2010

Abstract local cohomology functors

We propose to define the notion of abstract local cohomology functors. The derived functors of the ordinary local cohomology functor with support in the closed subset defined by an ideal and the generalized local cohomology functor associated with a given pair of ideals are characterized as elements of the set of all the abstract local cohomology functors.

math.AC↗

arXiv2008

Local cohomology based on a nonclosed support defined by a pair of ideals

We introduce an idea for generalization of a local cohomology module, which we call a local cohomology module with respect to a pair of ideals (I,J), and study their various properties. Some vanishing and nonvanishing theorems are given for this generalized version of local cohomology. We also discuss its connection with the ordinary local cohomology.

math.AC↗