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Related papers: On the combinatorics of gentle algebras

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We show that many tame modules of the quantum toroidal $\mathfrak{gl}_2$ algebra can be explicitly constructed in a purely combinatorial way using the theory of $q$-characters. The examples include families of evaluation modules obtained…

Quantum Algebra · Mathematics 2026-01-06 Michio Jimbo , Evgeny Mukhin

This paper investigates finiteness conditions for gentle and skew-gentle algebras. First, we prove that a skew-gentle algebra is $\tau$-tilting finite if and only if it is representation-finite, which extends the result for gentle algebras…

Representation Theory · Mathematics 2026-01-01 Wen Chang , Haibo Jin , Sibylle Schroll , Qi Wang

The notion of (semi)bricks, regarded as a generalization of (semi)simple modules, appeared in a paper of Ringel in 1976. In recent years, there has been several new developments motivated by links to {\tau}-tilting theory studied by…

Representation Theory · Mathematics 2023-05-09 Yingying Zhang

From Smyth's classification, modular compactifications of pointed smooth rational curves are indexed by combinatorial data, so-called extremal assignments. We explore their combinatorial structures and show that any extremal assignment is a…

Algebraic Geometry · Mathematics 2015-08-18 Han-Bom Moon , Charles Summers , James von Albade , Ranze Xie

The bricks over preprojective algebras of type A are known to be in bijection with certain combinatorial objects called "arcs". In this paper, we show how one can use arcs to compute bases for the Hom-spaces and first extension spaces…

Representation Theory · Mathematics 2024-08-23 Eric J. Hanson , Xinrui You

We confirm a conjecture by Lekili and Polishchuk that the geometric invariants which they construct for homologically smooth graded (not necessarily proper) gentle algebras form a complete derived invariant. Hence, we obtain a complete…

Representation Theory · Mathematics 2025-03-21 Haibo Jin , Sibylle Schroll , Zhengfang Wang

In representation theory of finite-dimensional algebras, (semi)bricks are a generalization of (semi)simple modules, and they have long been studied. The aim of this paper is to study semibricks from the point of view of $\tau$-tilting…

Representation Theory · Mathematics 2018-06-07 Sota Asai

We study the affine schemes of modules over gentle algebras. We describe the smooth points of these schemes, and we also analyze their irreducible components in detail. Several of our results generalize formerly known results, e.g. by…

Representation Theory · Mathematics 2021-12-23 Christof Geiß , Daniel Labardini-Fragoso , Jan Schröer

We construct combinatorial (involutory) Gelfand models for the following diagram algebras in the case when they are semi-simple: Brauer algebra, its partial analogue, walled Brauer algebra, its partial analogue, Temperley-Lieb algebra, its…

Representation Theory · Mathematics 2014-03-13 Volodymyr Mazorchuk

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 prove a multiplication formula for cluster characters induced by generating extensions in a gentle algebra A, generalizing a result of Cerulli Irelli, Esposito, Franzen, Reineke. In the case where A is the gentle algebra of a…

Representation Theory · Mathematics 2025-09-09 Azzurra Ciliberti

Enomoto and Sakai classified IE-closed subcategories over hereditary algebras via twin rigid modules. However, this classification inherently relies on the vanishing of second extension spaces, thus failing for arbitrary finite-dimensional…

Representation Theory · Mathematics 2026-04-03 Hanpeng Gao , Dajun Liu , Yu-Zhe Liu

To each skew-gentle algebra, one can assign a gentle algebra in terms of combinatorial data. In order to relate the structures of the two algebras, we establish a homological epimorphism and a recollement of derived module categories. This…

Representation Theory · Mathematics 2024-01-08 Yiping Chen

Support $\tau$-tilting modules correspond to some classes of categorical objects bijectively, such as two-term tilting complexes for any finite dimensional symmetric algebra. This fact motivates us to classify support $\tau$-tilting modules…

Representation Theory · Mathematics 2020-04-28 Ryotaro Koshio , Yuta Kozakai

Let $B$ be an one-point extension of a finite dimensional $k$-algebra $A$ by a simple $A$-module at a source point $i$. In this paper, we classify the $\tau$-tilting modules over $B$. Moreover, it is shown that there are equations $$|\tilt…

Representation Theory · Mathematics 2021-02-03 Hanpeng Gao

Szemeredi's Regularity Lemma is a very useful tool of extremal combinatorics. Recently, several refinements of this seminal result were obtained for special, more structured classes of graphs. We survey these results in their rich…

Combinatorics · Mathematics 2020-03-31 Yiting Jiang , Jaroslav Nesetril , Patrice Ossona de Mendez , Sebastian Siebertz

Let $B$ be the one-point extension algebra of $A$ by an $A$-module $X$. We proved that every support $\tau$-tilting $A$-module can be extended to be a support $\tau$-tilting $B$-module by two different ways. As a consequence, it is shown…

Representation Theory · Mathematics 2020-08-28 Hanpeng Gao , Zongzhen Xie

The aim of this paper is to describe the classes of strongly flat and weakly cotorsion modules with respect to a multiplicative subset or a finite collection of multiplicative subsets in a commutative ring. The strongly flat modules are…

Commutative Algebra · Mathematics 2019-04-08 Leonid Positselski , Alexander Slavik

Let $(\mbox{mod} \Lambda',\mbox{mod} \Lambda,\mbox{mod} \Lambda'')$ be a recollement of abelian categories for artin algebras $\Lambda'$, $\Lambda$ and $\Lambda''$. Under certain conditions, we present an explicit construction of gluing of…

Category Theory · Mathematics 2020-11-26 Xin Ma , Zongzhen Xie , Tiwei Zhao

Important objects of study in $\tau$-tilting theory include the $\tau$-tilting pairs over an algebra on the form $kQ/I$, with $kQ$ being a path algebra and $I$ an admissible ideal. In this paper, we study aspects of the combinatorics of…

Representation Theory · Mathematics 2021-09-27 Håvard Utne Terland