arXiv subjects

Jiaqun Wei

Publications and source records attributed to Jiaqun Wei.

At least 37 records · Page 2Linked to original sources

arXiv2024

Some properties of congruence lattices of path semigroups

Each quiver corresponds to a path semigroup, and such a path semigroup also corresponds to an associative K-algebra over an algebraically closed field K. Let Q be a quiver and S_Q, KQ be its path semigroup, path algebra, respectively. In this paper, we study some properties of the congruence lattice of S_Q. First, we show that there is a one-to-one correspondence between congruences on S and certain algebraic ideals of KQ. Based on such a description, we consider acyclic quivers and show that the congruence latices of such path semigroups are strong upper semimodular but not necessarily lower semimodular. Moreover, we provide some equivalent conditions for the congruence lattices to be modular and distributive.

math.GR↗

arXiv2024

Silting objects and torsion pairs in comma categories

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, D2) are torsion pairs if and only if the induced two pairs in the special comma category are torsion pairs under certain conditions.

math.RA↗

arXiv2024

Cluster characters for 2-Calabi-Yau Frobenius extriangulated categories

We define the cluster characters for 2-Calabi-Yau Frobenius extriangulated categories with cluster tilting objects. This provides a unified framework of cluster characters in 2-Calabi-Yau triangulated categories and 2-Calabi-Yau Frobenius exact categories given by Palu and Fu-Keller, respectively

math.RT↗

arXiv2024

Recollements and $n$-cotorsion pairs

In the present paper, we study the relationships of $n$-cotorsion pairs among three abelian categories in a recollement. Under certain conditions, we present an explicit construction of gluing of $n$-cotorsion pairs in an abelian category $\mathcal{D}$ with respect to $n$-cotorsion pairs in abelian categories $\mathcal{D}^{'}$, $\mathcal{D}^{''}$ respectively. On the other hand, we study the construction of $n$-cotorsion pairs in abelian categories $\mathcal{D}^{'}$, $\mathcal{D}^{''}$ obtained from $n$-cotorsion pairs in an abelian category $\mathcal{D}$.

math.CT↗

arXiv2024

Strongly $n$-AIR-tilting modules

We introduce the notion of (strongly) $n$-AIR-tilting modules, which is a high dimension version of support $τ$-tilting modules. The relations between them and $n$-silting modules and $n$-quasi-tilting modules, as well as generalized two-term silting complexes, are investigated. Our results particularly suggest a way to negate the rank question for silting complexes.

math.RT↗

arXiv2023

The Auslander-Reiten theory of the morphism category of projective modules

We investigate the structure of certain almost split sequences in $\mathcal{P}(Λ)$, i.e., the category of morphisms between projective modules over an Artin algebra $Λ$. The category $\mathcal{P}(Λ)$ has very nice properties and is closely related to $τ$-tilting theory, $g$-vectors, and Auslander-Reiten theory. We provide explicit constructions of certain almost split sequences ending at or starting from certain objects. Applications, such as to $g$-vectors, are given. As a byproduct, we also show that there exists an injection from Morita equivalence classes of Artin algebras to equivalence classes of 0-Auslander exact categories.

math.RT↗

arXiv2023

Distributivity in congruence lattices of graph inverse semigroups

Let Γ be a directed graph and Inv(Γ) be the graph inverse semigroup of Γ. Luo and Wang [7] showed that the congruence lattice C(Inv(Γ)) of any graph inverse semigroup Inv(Γ) is upper semimodular, but not lower semimodular in general. Anagnostopoulou-Merkouri, Mesyan and Mitchell characterized the directed graph Γ for which C(Inv(Γ)) is lower semimodular [2]. In the present paper, we show that the lower semimodularity, modularity and distributivity in the congruence lattice C(Inv(Γ)) of any graph inverse semigroup Inv(Γ) are equivalent.

math.GR↗

arXiv2022

Sincere silting modules and vanishing conditions

Let $R$ be a perfect ring and $T$ be an $R$-module. We study characterizations of sincere modules, sincere silting modules and tilting modules in terms of various vanishing conditions. It is proved that $T$ is sincere silting if and only if $T$ is presilting satisfing the vanishing condition $\mathrm{KerExt}^{0\le i\le 1}_R(T,-)=0$, and that $T$ is tilting if and only if $\mathrm{Ker}\mathrm{Ext}^{0\leqslant i\leqslant 1}_{R}(T,-)=0$ and $\mathrm{Gen}T\subseteq \mathrm{Ker}\mathrm{Ext}^{1\leqslant i\leqslant 2}_{R}(T,-)$. As an application, we prove that a sincere silting $R$-module $T$ of finite projective dimension is tilting if and only if $\mathrm{Ext}^{i}_{R}(T,T^{(J)})=0$ for all sets $J$ and all integer $i\ge 1$. This not only extends a main result of Zhang [14]from finitely generated modules over Artin algebras to infinitely generated modules over more general rings, but also gives it a different proof without using the functor $τ$ and Auslander-Reiten formula.

math.RT↗

arXiv2022

Semibricks, torsion-free classes and the Jordan-Hölder property

Let $\mathscr{C}$ be an extriangulated category and $\mathcal{X}$ be a semibrick in $\mathscr{C}$. Let $\mathcal{T}$ be the filtration subcategory generated by $\mathcal{X}$. We introduce the weak Jordan-Hölder property (WJHP) and Jordan-Hölder property (JHP) in $\mathscr{C}$ and show that $\mathcal{T}$ satisfies (WJHP). Furthermore, $\mathcal{T}$ satisfies (JHP) if and only if $\mathcal{X}$ is proper. Using reflection functors and $c$-sortable elements, we give a combinatorial criterion for the torsion-free class satisfying (JHP) in the representation category of a quiver of type $A$.

math.RT↗

arXiv2022

Ideal approximation in $n$-exangulated categories

In this paper, we study the ideal approximation theory associated to almost $n$-exact structures in the $n$-exangulated category. The notions of $n$-ideal cotorsion pairs and $n$-$\mathbb{F}$-phantom morphisms are introduced and studied. In particular, let $\mathscr{C}$ be an extriangulated category which satisfies the condition (WIC) and $\mathcal{T}$ be a nicely embedded $n$-cluster tilting subcategory of $\mathscr{C}$, we prove Salce's Lemma in $\mathcal{T}$.

math.CT↗

arXiv2022

Balanced pairs and tilting modules in recollement

In this paper, firstly, we mainly study the relationship of balanced pairs among three Abelian categories in a recollement. As an application of admissible balanced pairs, we introduce the notion of the relative tilting modules, and give a characterization of relative tilting modules, which similar to Bazzoni characterization of n-tilting modules [4]. Finally, we mainly consider the relationship of relative tilting modules in a recollement.

math.CT↗

arXiv2022

Star modules with respect to balanced pair

n this article, firstly, we introduce the notion of star modules with respect to a balanced pair and obtain some properties. We mainly give the relationship between n-X star modules and n-X tilting modules [9], and a new characterization of n-X tilting modules.

math.CT↗

arXiv2022

Relative AR-correspondence, co-t-structure and silting pair

As a generalization of tilting pair, which was introduced by Miyashita in \cite{YM}, the notion of silting pair is introduced in this paper. The authors extends a characterization of tilting modules given by Bazzoni \cite[Theorem~3.11]{BS} to silting pairs, and proves that there is an one-to-one correspondence between equivalent classes of silting pairs and certain subcategories which satisfy some conditions. Furthermore, the authors also gives a bijection between equivalent class of silting pairs and bounded above co-t-structure.

math.CT↗

arXiv2021

Hall algebras of extriangulated categories

Recently, Nakaoka and Palu introduced a notion of extriangulated categories. This is a unification of exact categories and triangulated categories. In this paper, we generalize the definitions of Hall algebras of exact categories and triangulated categories to extriangulated categories.

math.RT↗

arXiv2021

Gorenstein syzygy objects in extriangulated categories

We give the definition of Gorenstein syzygy objects in extriangulated categories and obtain a characterization. For a recollement of extriangulated categories, we mainly show that Gorenstein syzygy objects induce a new Gorenstein syzygy objects under certain conditions, and prove that Gorenstein syzygy objects induce a new Gorenstein syzygy objects under certain conditions.

math.KT↗

arXiv2020

$ξ$-tilting objects in extriangulated categories

Extriangulated categories were introduced by Nakaoka and Palu by extracting the similarities between exact categories and triangulated categories. In this article, we introduce and study the notion of $ξ$-tilting object in an extriangulated category, where $ξ$ is a proper class of $\mathbb{E}$-triangles. This extends results in \cite{YGH_2020}.

math.RT↗

arXiv2020

Recollements of extriangulated categories

We give a simultaneous generalization of recollements of abelian categories and triangulated categories, which we call recollements of extriangulated categories. For a recollement $(\mathcal{A}$, $\mathcal{B}$, $\mathcal{C})$ of extriangulated categories, we show that cotorsion pairs in $\mathcal{A}$ and $\mathcal{C}$ induce cotorsion pairs in $\mathcal{B}$ under certain conditions. As an application, our main result recovers a result given by Chen for recollements of triangulated categories, and it also shows a new phenomena when it is applied to abelian categories.

math.RT↗

arXiv2020

Semibricks in extriangulated categories

Let $\mathcal{X}$ be a semibrick in an extriangulated category $\mathscr{C}$. Let $\mathcal{T}$ be the filtration subcategory generated by $\mathcal{X}$. We give a one-to-one correspondence between simple semibricks and length wide subcategories in $\mathscr{C}$. This generalizes a bijection given by Ringel in module categories, which has been generalized by Enomoto to exact categories. Moreover, we also give a one-to-one correspondence between cotorsion pairs in $\mathcal{T}$ and certain subsets of $\mathcal{X}$. Applying to the simple minded systems of an triangulated category, we recover a result given by Dugas.

math.RT↗