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 …

Almost finite modules

D Apassov - Communications in Algebra, 1999 - Taylor & Francis
Assume that ϕ (R, m, k)→(S, n, l) is a local homomorphism between commutative noetherian
local rings R and S. We say that an S-module M is almost finite over R if it is finitely …

Persistence of homology over commutative noetherian rings

LL Avramov, SB Iyengar, S Nasseh, K Sather-Wagstaff - Journal of Algebra, 2022 - Elsevier
We describe new classes of noetherian local rings R whose finitely generated modules M
have the property that Tor i R (M, M)= 0 for i≫ 0 implies that M has finite projective …

Cofiniteness and finiteness of generalized local cohomology modules

L Chu - Bulletin of the Australian Mathematical Society, 2009 - cambridge.org
Let I be an ideal of a commutative Noetherian local ring R, and M and N two finitely
generated modules. Let t be a positive integer. We mainly prove that (i) if HIi (M, N) is …

[PDF][PDF] Modules of G-dimension zero over local rings of depth two

R Takahashi - Illinois Journal of Mathematics, 2004 - projecteuclid.org
Let $ R $ be a commutative noetherian local ring. Denote by $\mod R $ the category of
finitely generated $ R $-modules, and by ${\mathcal G}(R) $ the full subcategory of $\mod R …

Openness of various loci over Noetherian rings

K Kimura - Journal of Algebra, 2023 - Elsevier
In this paper, we consider the openness of the P-locus of a finitely generated module over a
commutative noetherian ring in the case where P is each of the properties FID, Gor, Can …

MODULES OVER UNRAMIFIED REGULAR LOCAL RINGS¹

M Auslander - Selected Works of Maurice Auslander, 1999 - books.google.com
Throughout this paper we assume that all rings are commutative, noetherian rings with unit
and that all modules are finitely generated and unitary. The main object of study is what it …

Cofinite modules and local cohomology

D Delfino, T Marley - Journal of Pure and Applied Algebra, 1997 - Elsevier
We show that if M is a finitely generated module over a commutative Noetherian local ring R
and I is a dimension one ideal of R (ie, dim RI= 1), then the local cohomology modules HIi …

Tests for injectivity of modules over commutative rings

LW Christensen, SB Iyengar - Collectanea mathematica, 2017 - Springer
It is proved that a module M over a commutative noetherian ring R is injective if Ext _ R^ i
((R/\mathfrak p) _\mathfrak p, M)= 0 Ext R i ((R/p) p, M)= 0 holds for every i\geqslant 1 i⩾ 1 …

Cofiniteness over Noetherian complete local rings

K Bahmanpour - Communications in Algebra, 2019 - Taylor & Francis
In this article, we prove the following generalization of a result of Hartshorne: Let (S, n) be a
regular local ring of dimension 4. Assume that x, y, u, v is a regular system of parameters for …