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In extended hearts of bounded $t$-structures on a triangulated category, we provide a Happel-Reiten-Smalo tilting theorem and a characterization for $s$-torsion pairs. Applying these to $m$-extended module categories, we characterize…

Representation Theory · Mathematics 2025-01-09 Yu Zhou

To any dg-category $T$ (over some base ring $k$), we define a $D^{-}$-stack $\mathcal{M}_{T}$ in the sense of \cite{hagII}, classifying certain $T^{op}$-dg-modules. When $T$ is saturated, $\mathcal{M}_{T}$ classifies compact objects in the…

Algebraic Geometry · Mathematics 2007-05-23 B. Toen , M. Vaquie

We prove that the Auslander class determined by a semidualizing module is the left half of a perfect cotorsion pair. We also prove that the Bass class determined by a semidualizing module is preenveloping.

Commutative Algebra · Mathematics 2007-05-23 Edgar E. Enochs , Henrik Holm

We present a setting for the study of torsion theories in general categories. The idea is to associate, with any pair ($\mathcal T$, $\mathcal F$) of full replete subcategories in a category $\mathcal C$, the corresponding full subcategory…

Category Theory · Mathematics 2022-01-04 Alberto Facchini , Carmelo Finocchiaro , Marino Gran

Torsion theories play an important role in abelian categories and they have been widely studied in the last sixty years. In recent years, with the introduction of pretorsion theories, the definition has been extended to general…

Category Theory · Mathematics 2024-07-17 Federico Campanini , Francesca Fedele

In this paper, we study the torsion subgroup, which is denoted by ${\rm TK}_1(E)$, of the Whitehead group $E^*/[E^*,E^*]$ of a graded division algebra $E$ which is finite dimensional over its center. In particular, we provide formulas for…

Rings and Algebras · Mathematics 2024-04-11 Huynh Viet Khanh , Nguyen Duc Anh Khoa , Nguyen Dinh Anh Khoi

Let $\mathcal B$ be an extriangulated category with enough projectives and enough injectives. We define a proper $m$-term subcategory $\mathcal G$ on $\mathcal B$, which is an extriangulated subcategory. Then we give a correspondence…

Representation Theory · Mathematics 2020-12-15 Yu Liu , Panyue Zhou

In the category of finitely generated modules over an artinian ring, we classify all the abelian exact subcategories closed under predecessors or, equivalently, all the split torsion pairs with torsion-free class closed under quotients.

Rings and Algebras · Mathematics 2007-05-23 Ibrahim Assem , Manuel Saorin

Let $K$ be a multiquadratic extension of $\mathbb{Q}$ and let $\text{Cl}^{+}(K)$ be its narrow class group. Recently, the authors \cite{KP} gave a bound for $|\text{Cl}^{+}(K)[2]|$ only in terms of the degree of $K$ and the number of…

Number Theory · Mathematics 2021-03-09 Peter Koymans , Carlo Pagano

For a left artinian ring A, we study the lattice torsA of torsion pairs in the category of finitely generated A-modules by considering an isomorphic lattice formed by certain closed sets in a topological space associated to A, the Ziegler…

Representation Theory · Mathematics 2026-02-23 Lidia Angeleri Hügel

Following arguments that the (hidden) M-algebra serves as the maximal super-exceptional tangent space for 11D supergravity, we make explicit here its integration to a (super-Lie) group. This is equipped with a left-invariant extension of…

High Energy Physics - Theory · Physics 2026-01-12 Grigorios Giotopoulos , Hisham Sati , Urs Schreiber

In this paper, we first give a characterization of silting objects in the comma category Assume that C1 and C2 are two subcategories of left R-modules, D1 and D2 be two subcategories of left S-modules. We mainly prove that (C1, C2) and (D1,…

Rings and Algebras · Mathematics 2024-05-28 Peiyu Zhang , Xinyu Wang , Dajun Liu , Li Wang , Jiaqun Wei

Let $T$ be a monad on a category $\mathscr{C}$. In this paper, we introduce the notion of higher derivations on the monad $T$ and characterize them in terms of ordinary derivations on $T$. We also define higher derivations on modules over…

Category Theory · Mathematics 2026-01-28 Dipti Paik , Divya Ahuja , Surjeet Kour

We determine all composition-closed equational classes of Boolean functions. These classes provide a natural generalization of clones and iterative algebras: they are closed under composition, permutation and identification…

Rings and Algebras · Mathematics 2011-02-23 Tamás Waldhauser

In this paper we introduce $n\mathbb{Z}$-abelian and $n\mathbb{Z}$-exact categories by axiomatising properties of $n\mathbb{Z}$-cluster tilting subcategories. We study this categories and show that every $n\mathbb{Z}$-cluster tilting…

Category Theory · Mathematics 2022-02-15 Ramin Ebrahimi , Alireza Nasr-Isfahani

We show that every higher Auslander algebra $A_{n+1}^d$ of type $\mathbb{A}$ such that $\gcd(n,d)=1$ is derived equivalent to a certain replicated algebra $B=B_0^{(n+d)}$. Moreover ${\rm{gldim}} B = nd$ and $B$ admits an $nd$-cluster…

Representation Theory · Mathematics 2025-12-01 Wei Xing

The main result of this paper is that there is sometimes a triangulated equivalence between $D_Q( A )$, the $Q$-shaped derived category of an algebra $A$, and $D( B )$, the classic derived category of a different algebra $B$. By…

Representation Theory · Mathematics 2025-01-22 Sira Gratz , Henrik Holm , Peter Jorgensen , Greg Stevenson

In this article, we prove that if $(\mathcal A ,\mathcal B,\mathcal C)$ is a recollement of extriangulated categories, then torsion pairs in $\mathcal A$ and $\mathcal C$ can induce torsion pairs in $\mathcal B$, and the converse holds…

Representation Theory · Mathematics 2023-02-07 Jian He , Yonggang Hu , Panyue Zhou

Let A be an abelian variety defined over a number field K, the number of torsion points rational over a finite extension L is bounded polynomially in terms of the degree [L : K]. When A is isogenous to a product of simple abelian varieties…

Number Theory · Mathematics 2016-12-02 Marc Hindry , Nicolas Ratazzi

The notion of a pseudo cluster tilting subcategory $\mathcal X$ in an extriangulated category $\mathcal C$ is defined in this article. We prove that the quotient category $\mathcal C/\mathcal X$, obtained by factoring an extriangulated…

Representation Theory · Mathematics 2023-09-11 Jian He , Jing He