倾斜代数的一类单点扩张(Ⅱ)

设A遗传,(A,T,B)是倾斜对,B~N=Hom_A(T,M),M∈G(T).本文首先给出A=A[M]上倾斜模T=T⊕P_A(ω)诱导的B=B[N]-mod中Torsion theory((T),(T))可裂的充要条件;然后利用它对B-mod的AR箭图的结构作了刻划;得到了遗传代数借助不可分解内射模的单点扩张代数的表示型的完整刻划,作为推论给出了Happel提出的公开问题的部分回答.     

Dn型路代数本性倾斜模的一个必要条件

倾斜理论是研究代数表示理论的重要工具之一．本文主要对Dn（n≥4），E6，E7，E8型路代数倾斜模在其对应的AR-箭图上的结构持点进行研究．通过对Dn（n≥4），上E6，E7，E8型路代数A的AR-箭图ΓA分析证明了Dn≥4），E6，E7，E8型路代数本性慨斜模TA的一个必要条件是：在A的AR-箭图ΓA的每个边缘的r-轨道都有TA的不可分解直和项对应的点．     

BB-倾斜模与Hammock

证明存在Hammock位于有限表示型代数A上BB-倾斜模T_A诱导的AR-箭图上和代数B=End(T_A)的AR-箭图上,并用Hammock对BB-倾斜模T_A进行刻画.     

Dn型路代数倾斜模与AR箭图边缘

代数表示理论是上个世纪七十年代初兴起的代数学的—个新的分支,而倾斜理论是研究代数表示理论的重要工具之一．本文主要对Dn型路代数倾斜模在其对应的AR-箭图上的结构特点进行研究．通过对Dn型路代数A的AR-箭图ΓA分析,证明了：Dn型路代数倾斜模T的—个必要条件是。〈T〉中至少有三个边缘点．     

AR箭图的直向分支

本文研究无限表示型代数AR箭图的分支的直向性,包括直向分支的判定;新的直向分支的构造;具有ZΔ分支的平凡扩张代数T(A)的确定,其中A是重复倾斜代数.     

对偶扩张代数的Frobenius态射和固定点代数

设A是由箭图Q和关系I所确定的代数,D(A)是代数A的对偶扩张代数, 对应的箭图Q*和关系I*由Q和I决定．本文证明:带关系箭图(Q*,I*)的自同构由带关系箭图(Q,I)的自同构决定;D(A)的Frobenius态射由A的Frobenius态射完全决定;代数D(A)的固定点代数同构于相应的代数A的固定点代数与A°P的固定点代数的张量积,特别地,当Q为单的箭图时,代数D(A)的固定点代数同构于代数A的固定点代数的对偶扩张代数．     

对偶扩张代数的倾斜模及其导出的挠理论 *

设A是有限维代数 ,R为代数A的对偶扩张代数 .研究了倾斜理论及其导出的挠理论 .首先通过函子研究了倾斜R 模与倾斜A 模的重要联系 ,给出了M _AR是一个倾斜R-模的充分必要条件.其次讨论了两个倾斜模给出模范畴中同一子范畴的不同等价问题 .对倾斜R-模M₁ AR和M₂ AR ,证明了它们导出modR中相同的挠理论当且仅当M₁和M₂ 导出modA中相同的挠理论 .     

关于n-BB-倾斜模的一个注记

设A是一个域k上的基本有限维代数.本文证明了如果AT是一个n-BB-倾斜模,那么TB亦为n-BB-倾斜模,其中B=End(AT).进一步,如果AT是一个n-APR-倾斜模,那么TB亦为n-APR-倾斜模.最后,把本文的结果应用到一个具有n-APR-倾斜模AT的代数A上,得到A是n-表示-有限的(无限的)当且仅当B是n-表示-有限的(无限的).     

A~n型例外序列的自同态代数的表示型

令Ｆ是一个代数闭域，→Δ是Ａｎ型ｑｕｉｖｅｒ，本文利用垂直范畴证明了Ｆ→Δ上例外序列的自同态代数是有限多个Ａｍ（ｍｎ）型倾斜代数的直和，从而Ａｎ型例外序列的自同态代数是有限表示型的．     

(*)-serial Incidence代数(英文)

设K是一个代数闭域,A是域K上一个有限维代数.我们利用箭图方法给出了(*)-serial incidence代数的分类.     

THE REGULAR COMPONENTS OF THE AUSLANDER-REITEN QUIVER OF A TILTED ALGEBRA

Let B be a connected finite-dimensional hereditary algebra of infinite representationtype.It is shown that there exists a regular tilting B-module if and only if B is wild andhas at least three simple modules.In this way,the author determines the possible form ofregular components which arise as a connecting component of the Auslander-Reitenquiver Γ(A)of a tilted algebra A.The second result asserts that for a tilted algebra A,any regular component of Γ(A)which is not a connecting component,is quasi-serial.     

On the quiver with relations of a quasitilted algebra and applications

In this paper we discuss, in terms of quiver with relations, su?cient and necessary conditions for an algebra to be a quasitilted algebra. We start with an algebra with global dimension at most two and we give a su?cient condition to be a quasitilted algebra. We show that this condition is not necessary. In the case of a strongly simply connected schurian algebra, we discuss necessary conditions, and combining both types of conditions, we are able to analyze if some given algebra is quasitilted. As an application we obtain the quiver with relations of all the tilted and cluster tilted algebras of Dynkin type E_p.     

Quivers with Relations and Cluster Tilted Algebras

Cluster algebras were introduced by S. Fomin and A. Zelevinsky in connection with dual canonical bases. To a cluster algebra of simply laced Dynkin type one can associate the cluster category. Any cluster of the cluster algebra corresponds to a tilting object in the cluster category. The cluster tilted algebra is the algebra of endomorphisms of that tilting object. Viewing the cluster tilted algebra as a path algebra of a quiver with relations, we prove in this paper that the quiver of the cluster tilted algebra is equal to the cluster diagram. We study also the relations. As an application of these results, we answer several conjectures on the connection between cluster algebras and quiver representations.Presented by V. Dlab.     

Constructing tilted algebras from cluster-tilted algebras

Any cluster-tilted algebra is the relation extension of a tilted algebra. Given the distribution of a cluster-tilting object in the Auslander–Reiten quiver of the cluster category, we present a method to construct all tilted algebras whose relation extension is the endomorphism ring of this cluster-tilting object.     

Maximal Green Sequences for Preprojective Algebras

Maximal green sequences were introduced as combinatorical counterpart for Donaldson-Thomas invariants for 2-acyclic quivers with potential by B. Keller. We take the categorical notion and introduce maximal green sequences for hearts of bounded t-structures of triangulated categories that can be tilted indefinitely. We study the case where the heart is the category of modules over the preprojective algebra of a quiver without loops. The combinatorical counterpart of maximal green sequences for Dynkin quivers are maximal chains in the Hasse quiver of basic support τ-tilting modules. We show that a quiver has a maximal green sequence if and only if it is of Dynkin type. More generally, we study module categories for finite-dimensional algebras with finitely many bricks.     

On the noncommutative Donaldson-Thomas invariants arising from brane tilings

Given a brane tiling, that is a bipartite graph on a torus, we can associate with it a quiver potential and a quiver potential algebra. Under certain consistency conditions on a brane tiling, we prove a formula for the Donaldson-Thomas type invariants of the moduli space of framed cyclic modules over the corresponding quiver potential algebra. We relate this formula with the counting of perfect matchings of the periodic plane tiling corresponding to the brane tiling. We prove that the same consistency conditions imply that the quiver potential algebra is a 3-Calabi-Yau algebra. We also formulate a rationality conjecture for the generating functions of the Donaldson-Thomas type invariants.     

On Quiver Grassmannians and Orbit Closures for Gen-Finite Modules

We show that endomorphism rings of cogenerators in the module category of a finite-dimensional algebra A admit a canonical tilting module, whose tilted algebra B is related to A by a recollement. Let M be a gen-finite A-module, meaning there are only finitely many indecomposable modules generated by M. Using the canonical tilts of endomorphism algebras of suitable cogenerators associated to M, and the resulting recollements, we construct desingularisations of the orbit closure and quiver Grassmannians of M, thus generalising all results from previous work of Crawley-Boevey and the second author in 2017. We provide dual versions of the key results, in order to also treat cogen-finite modules.

     

Auslander–Reiten Components with Sectional Bypasses

In this work, we will prove that the modules lying in a sectional bypass of an arrow in the Auslander–Reiten quiver of an artin algebra, are either all left stable or all right stable, but not τ-periodic. Moreover, if such a bypass exists, then the Auslander–Reiten quiver has an infinite left or right stable component which contains a section with a bypass.     

Cluster Tilted Algebras with a Cyclically Oriented Quiver

In association with a finite dimensional algebra A of global dimension two, we consider the endomorphism algebra of A, viewed as an object in the triangulated hull of the orbit category of the bounded derived category, in the sense of Amiot. We characterize the algebras A of global dimension two such that its endomorphism algebra is isomorphic to a cluster-tilted algebra with a cyclically oriented quiver. Furthermore, in the case that the cluster tilted algebra with a cyclically oriented quiver is of Dynkin or extended Dynkin type then A is derived equivalent to a hereditary algebra of the same type.