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The cohomology annihilator of a noetherian ring that is finitely generated as a module over its center is introduced. Results are established linking the existence of non-trivial cohomology annihilators and the existence of strong…

Commutative Algebra · Mathematics 2015-04-27 Srikanth B. Iyengar , Ryo Takahashi

Mutations occur in multiple algebraic contexts, often enjoying good combinatorial properties. In this paper we study mutations of pure-injective cosilting objects in compactly generated triangulated categories from a topological point of…

Representation Theory · Mathematics 2025-03-21 Michal Hrbek , Sergio Pavon , Jorge Vitória

We prove that the integral cohomology modulo torsion of a rationally connected threefold comes from the integral cohomology of a smooth curve via the cylinder homomorphism associated to a family of $1$-cycles. Equivalently, it is of strong…

Algebraic Geometry · Mathematics 2022-12-21 Claire Voisin

In the papers of Nakaoka, he introduced the notion of hearts of (twin) cotorsion pairs on triangulated categories and showed that they have structures of (semi-) abelian categories. We study in this article a twin cotorsion pair (S,T),(U,V)…

Representation Theory · Mathematics 2019-02-21 Yu Liu

We study certain special tilting and cotilting modules for an algebra with positive dominant dimension, each of which is generated or cogenerated (and usually both) by projective-injectives. These modules have various interesting…

Representation Theory · Mathematics 2023-06-22 Matthew Pressland , Julia Sauter

We study Tate-Vogel and relative cohomologies of complexes by applying the model structure induced by a complete hereditary cotorsion pair ($\A$, $\B$) of modules. We show first that the class of complexes admitting a complete $\A$…

Rings and Algebras · Mathematics 2020-08-25 Jiangsheng Hu , Huanhuan Li , Jiaqun Wei , Xiaoyan Yang , Nanqing Ding

We construct new complete cotorsion pairs in the categories of modules and chain complexes over a Gorenstein ring $R$, from the notions of Gorenstein homological dimensions, in order to obtain new Abelian model structures on both…

Category Theory · Mathematics 2014-05-22 Marco Pérez

We prove that the integral cohomology ring modulo torsion $H^*(\mathrm{Sym}^n X;\mathbb{Z})/\mathrm{Tor}$ for the symmetric product of a connected CW-complex $X$ of finite homology type is a functor of $H^*(X;\mathbb{Z})/\mathrm{Tor}$ (see…

Algebraic Topology · Mathematics 2025-03-25 Dmitry V. Gugnin

Let $R$ be a commutative ring, and let $S$ be a multiplicative subset of $R$. In this paper, we investigate the notion of $S$-cotorsion modules. An $R$-module $C$ is called $S$-cotorsion if $\text{Ext}^{1}_{R}(F,C) = 0$ for every $S$-flat…

Commutative Algebra · Mathematics 2024-09-02 Driss Bennis , Ayoub Bouziri

We study hearts of cotorsion pairs in triangulated and exact categories.We give a sufficient and necessary condition when the hearts have enough projectives. We also show in such condition they are equivalent to functor categories over…

Representation Theory · Mathematics 2020-03-17 Yu Liu

We examine the integral cohomology rings of certain families of $2n$-dimensional orbifolds $X$ that are equipped with a well-behaved action of the $n$-dimensional real torus. These orbifolds arise from two distinct but closely related…

Algebraic Topology · Mathematics 2018-03-16 Anthony Bahri , Soumen Sarkar , Jongbaek Song

Let R be a commutative noetherian ring. Denote by mod R the category of finitely generated R-modules. In this paper, we study n-torsionfree modules in the sense of Auslander and Bridger, by comparing them with n-syzygy modules, and modules…

Commutative Algebra · Mathematics 2021-01-13 Souvik Dey , Ryo Takahashi

We investigate Tate cohomology of modules over a commutative noetherian ring with respect to semidualizing modules. We identify classes of modules admitting Tate resolutions and analyze the interaction between the corresponding relative and…

Commutative Algebra · Mathematics 2009-07-29 Sean Sather-Wagstaff , Tirdad Sharif , Diana White

In this article, we give a generalization to injective modules by using $e$-exact sequences introduced by Akray in [1] and name it $e$-injective modules and investigate their properties. We reprove both Baer criterion and comparison theorem…

Commutative Algebra · Mathematics 2023-09-20 Runak H. Mustafa , Ismael Akray

The paper contains a collection of results related to weight structures, $t$-structures, and (more generally) to torsion pairs. For any weight structure $w$ we study (co)homological pure functors; these "ignore all weights except weight…

K-Theory and Homology · Mathematics 2019-10-15 Mikhail V. Bondarko

We study the lattice $\mathbf{tors}(A)$ of torsion pairs in the category $\mathrm{mod}(A)$ of finitely generated modules over an artinian ring $A$. It was shown by the authors in previous work that $\mathbf{tors}(A)$ is isomorphic to a…

Representation Theory · Mathematics 2026-02-18 Lidia Angeleri Hügel , Rosanna Laking , Francesco Sentieri

In this paper, we first construct some complete cotorson pairs on the category $\mathbb{C}_N(\mathcal{G})$ of unbounded $N$-complexes of Grothendieck category $\mathcal{G}$, from two given cotorsion pairs in $\mathcal{G}$. Next as an…

Representation Theory · Mathematics 2019-06-18 Payam Bahiraei

Motivated by its links to $\tau$-tilting theory, we introduce a generalization of cotorsion pairs in module categories. Such pairs are also linked to co-t-structures in corresponding triangulated categories, and to cotorsion pairs in…

Representation Theory · Mathematics 2021-11-23 Aslak Bakke Buan , Yu Zhou

We study classes of modules closed under direct sums, $\mathcal{M}$-submodules and $\mathcal{M}$-epimorphic images where $\mathcal{M}$ is either the class of embeddings, $RD$-embeddings or pure embeddings. We show that the…

Rings and Algebras · Mathematics 2024-08-19 Marcos Mazari-Armida , Jiri Rosicky

Let $R$ be a commutative Noetherian ring. We give criteria for flatness of $R$-modules in terms of associated primes and torsion-freeness of certain tensor products. This allows us to develop a criterion for regularity if $R$ has…

Commutative Algebra · Mathematics 2015-12-11 Neil Epstein , Yongwei Yao