Maximal Cohen–Macaulay tensor products and vanishing of Ext modules

K Kimura, Y Otake, R Takahashi - Bulletin of the London …, 2022 - Wiley Online Library
In this paper, we investigate the maximal Cohen–Macaulay property of tensor products of
modules, and then give criteria for projectivity of modules in terms of vanishing of Ext …

Hom and Ext, revisited

H Dao, M Eghbali, J Lyle - Journal of Algebra, 2021 - Elsevier
Let R be a commutative Noetherian local ring and M, N be finitely generated R-modules. We
prove a number of results of the form: if Hom R (M, N) has some nice properties and Ext R …

[HTML][HTML] Correspondence between trace ideals and birational extensions with application to the analysis of the Gorenstein property of rings

S Goto, R Isobe, S Kumashiro - Journal of Pure and Applied Algebra, 2020 - Elsevier
Over an arbitrary commutative ring, correspondences among three sets, the set of trace
ideals, the set of stable ideals, and the set of birational extensions of the base ring, are …

The reduction number of canonical ideals

S Kumashiro - Communications in Algebra, 2022 - Taylor & Francis
In this article, we introduce an invariant of Cohen-Macaulay local rings in terms of the
reduction number of canonical ideals. The invariant can be defined in arbitrary Cohen …

Residually faithful modules and the Cohen–Macaulay type of idealizations

S Goto, S Kumashiro, NTH Loan - Journal of the Mathematical …, 2019 - jstage.jst.go.jp
The Cohen–Macaulay type of idealizations of maximal Cohen–Macaulay modules over
Cohen–Macaulay local rings is closely explored. There are two extremal cases, one of …

The trace property in preenveloping classes

H Lindo, P Thompson - Proceedings of the American Mathematical Society …, 2023 - ams.org
We develop the theory of trace modules up to isomorphism and explore the relationship
between preenveloping classes of modules and the property of being a trace module …

When are trace ideals finite?

S Kumashiro - Mediterranean Journal of Mathematics, 2023 - Springer
In this paper, we study Noetherian local rings R having a finite number of trace ideals. We
proved that such rings are of dimension at most two. Furthermore, if the integral closure of …

Reflexive modules over the endomorphism algebras of reflexive trace ideals

N Endo, S Goto - Journal of Pure and Applied Algebra, 2024 - Elsevier
In the present paper we investigate reflexive modules over the endomorphism algebras of
reflexive trace ideals in a one-dimensional Cohen-Macaulay local ring. The main theorem …

When are the rings I:I Gorenstein?

N Endo, S Goto, S Iai, N Matsuoka - Communications in Algebra, 2023 - Taylor & Francis
Abstract Let I (≠ A) be an ideal of ad-dimensional Noetherian local ring A with ht AI≥ 2,
containing a non-zerodivisor. The problem of when the ring I: I= End AI is Gorenstein is …

[PDF][PDF] On generalized Gorenstein rings

S KUMASHIRO - (No Title), 2020 - opac.ll.chiba-u.jp
The notion of commutative rings is important in singularity theory, and it is deeply related to
various algebraic areas, say, algebraic geometry, representation theory, invariant theory …