半导出Hall代数的Gr?bner-Shirshov基

在Dynkin型Ringel-Hall代数中,不可分解表示同构类之间的所有拟交换关系之集构成由这些关系生成的理想的一个极小Gr?bner-Shirshov基,并且相应的不可约元素构成此Ringel-Hall代数的一组PBW基.本文的目的是将把此结果推广到Dynkin箭图的半导出Hall代数上去.为此,首先通过计算所有合成来证明不可分解表示同构类之间的所有拟交换关系之集是一个极小Gr?bner-Shirshov基.然后,作为一个应用,通过取所有不可约元素构造一组PBW基.     

G_(2)-型导出Hall代数的PBW基北大核心CSCD

在Dynkin型Ringel-Hall代数中,不可分解模同构类之间的所有拟交换关系的集合S构成理想Id(S)的一个极小Grobner-Shirshov基,并且对于S的所有不可约元素构成Ringel-Hall代数的一个PBW基.本文把此结果推广到G_(2)-型导出Hall代数上.首先用Auslander-Reiten箭图计算不可分解模同构类之间的所有拟交换关系,然后证明这些拟交换关系之间的所有合成都是平凡的,最后给出G_(2)-型导出Hall代数的一个PBW基.     

B_3型退化Ringel-Hall代数的Gr?bner-Shirshov基

利用Frobenius映射和一般扩张幺半群代数,得到B_3型退化Ringel-Hall代数的一组生成元和生成关系,进而构造了B_3型退化Ringel-Hall代数的Gr(o|¨)bnerShirshov基.     

Hall多项式

作为Hall代数的结构常数, Hall数和Hall多项式与对称群的表示和量子群的结构有紧密联系.本文首先引入经典Hall代数和Hall多项式的概念,并阐述其与对称函数的联系.其次,定义有限域上代数的Ringel-Hall代数,并简述其与量子群的关系.最后,本文在Dynkin箭图和仿射箭图情形下,讨论Hall多项式的存在性.     

A∞∞ _ 型 Ringel-Hall 代数

这是利用 A^∞_∞ -型 Ringel-Hall 代数研究sl ^∞_∞ -型量子群的两篇文章中的第一篇. 为此首先需要研究建立在任意域k 上的无限维路代数 kA^∞_∞ 的有限维表示. 在文章的第一部分, 我们给出了所有的不可分解 kA^∞_∞ - 表示, 并且清楚地刻画了它们之间的扩张关系; 在第二部分, 对于给定的有限域k, 我们研究了 Ringel-Hall 代数 H(kA^∞_∞). 主要观察是把H(kA^∞_∞) 看作 Ringel-Hall 代数 H(kA_∞) 的正向极限, 把 H(kA_∞) 看作Ringel-Hall 代数 H(kA_n) 的正向极限. 特别地, 我们得到了H(kA^∞_∞) 的一个 PBW-基, 并且 证明了H(kA^∞_∞) 恰好和它的合成子代数重合.     

An型路代数倾斜模的个数

本文证明APR-倾斜过程不改变Dynkin型路代数的倾斜模的个数,并给出计算An型 路代数的倾斜模的个数的递推公式.     

m-循环复形范畴的Bridgeland-Hall代数的余代数结构

设A是一个遗传Abel范畴且■是A的投射对象构成的满子范畴.本文主要研究胁循环复形范畴C_m(■)的Bridgeland-Hall代数的余代数结构(其中m≥2).受Yanagida工作的启发,我们在C_m(■)上定义一个新的正合结构,由此得到了其Bridgeland-Hall代数的余代数结构.同时,证明了存在A的扩展Ringel-Hall代数到m-循环复形范畴C_m(■)的Bridgeland-Hall代数的余代数嵌入.     

q-Schur超代数

本文总结了近期在q-Schur超代数、量子一般线性超群和它们的典范基以及不可约(多项式)表示方面的研究.首先给出了q-Schur超代数在三种不同背景下的定义和相应的基,并且刻画了这三组基之间的关系,接着描述了q-Schur超代数中的某些乘法公式及其在量子一般线性超群的新实现、q-Schur超代数的正则表示和量子一般线性超群的正部分的典范基的构造中的应用,同时给出了q-Schur超代数的半单性的判别条件.通过对Alperin的权猜想和Scott的置换表示理论的推广,本文得到了q-Schur超代数的不可约模分类.本文最后提到了在不引入量子坐标代数情形下构造无穷小和小q-Schur超代数的新方法.     

An型路代数倾斜模的个数

本文证明APR-倾斜过程不改变Dynkin型路代数的倾斜模的个数,并给出计算A_n型路代数的倾斜模的个数的递推公式.     

Gr?bner–Shirshov Basis of Derived Hall Algebra of Type A_n

We know that in Ringel–Hall algebra of Dynkin type, the set of all skew commutator relations between the iso-classes of indecomposable modules forms a minimal Gr?bner–Shirshov basis,and the corresponding irreducible elements forms a PBW type basis of the Ringel–Hall algebra. We aim to generalize this result to the derived Hall algebra DH(A_n) of type A_n. First, we compute all skew commutator relations between the iso-classes of indecomposable objects in the bounded derived category D~b(A_n) using the Auslander–Reiten quiver of D~b(A_n), and then we prove that all possible compositions between these skew commutator relations are trivial. As an application, we give a PBW type basis of DH(A_n).     

Skew-commutator relations and Gröbner-Shirshov basis of quantum group of type F 4

We give a Grobner-Shirshov basis of quantum group of type F4 by using the Ringel-Hall algebra approach. We compute all skew-commutator relations between the isoclasses of indecomposable representations of Ringel- Hall algebras of type F4 by using an ＇inductive＇ method. Precisely, we do not use the traditional way of computing the skew-commutative relations, that is first compute all Hall polynomials then compute the corresponding skew- commutator relations; instead, we compute the ＇easier＇ skew-commutator relations which correspond to those exact sequences with middle term indecomposable or the split exact sequences first, then ＇deduce＇ others from these ＇easier＇ ones and this in turn gives Hall polynomials as a byproduct. Then using the composition-diamond lemma prove that the set of these relations constitute a minimal CrSbner-Shirshov basis of the positive part of the quantum group of type F4. Dually, we get a Grobner-Shirshov basis of the negative part of the quantum group of type F4. And finally, we give a Gr6bner-Shirshov basis for the whole quantum group of type F4.     

A Parameterization of the Canonical Bases of Affine Modified Quantized Enveloping Algebras

For a symmetrizable Kac-Moody Lie algebra g, Lusztig introduced the corresponding modified quantized enveloping algebra˙U and its canonical basis˙B given by Lusztig in 1992. In this paper, in the case that g is a symmetric Kac-Moody Lie algebra of finite or affine type, the authors define a set M which depends only on the root category R and prove that there is a bijection between M and ˙B, where R is the T~2-orbit category of the bounded derived category of the corresponding Dynkin or tame quiver. The method in this paper is based on a result of Lin, Xiao and Zhang in 2011, which gives a PBW-type basis of U~+.     

Ringel–Hall Algebras of Quotient Algebras of Path Algebras

We determine the generating relations for Ringel–Hall algebras associated with quotient algebras of path algebras of Dynkin and tame quivers, and investigate their connection with composition subalgebras.     

A new approach to Kac's theorem on representations of valued quivers

By using the Ringel-Hall algebra approach we first present a new proof of Kac's theorem for species over a finite field. The method used here is quite different from earlier techniques. In [SV] Sevenhant and Van den Bergh have discovered an interesting relation between a conjecture of Kac on representations of quivers and the structure of the Ringel-Hall algebras in some special cases. We second show that this relation still holds for species. The research was supported in part by the NSF of China and the TRAPOYP.     

Skew differential operator algebras of twisted Hopf algebras

By introducing a twisted Hopf algebra we unify several important objects of study. Skew derivations of such an algebra are defined and the corresponding skew differential operator algebras are studied. This generalizes results in the Weyl algebra. Applying this investigation to the twisted Ringel-Hall algebra we get, in particular, a natural realization of the non-positive part of a quantized generalized Kac-Moody algebra, by identifying the canonical generators with some linear, skew differential operators. This also induces some algebras which are quantum-group like.     

Representation theory of Dynkin quivers. Three contributions

The representations of the Dynkin quivers and the corresponding Euclidean quivers are treated in many books. These notes provide three building blocks for dealing with representations of Dynkin (and Euclidean) quivers. They should be helpful as part of a direct approach to study represen-tations of quivers, and they shed some new light on properties of Dynkin and Euclidean quivers.     

Notes on piecewise-Koszul algebras

The relationships between piecewise-Koszul algebras and other “Koszul-type” algebras are discussed. The Yoneda-Ext algebra and the dual algebra of a piecewise-Koszul algebra are studied, and a sufficient condition for the dual algebra A ^! to be piecewise-Koszul is given. Finally, by studying the trivial extension algebras of the path algebras of Dynkin quivers in bipartite orientation, we give explicit constructions for piecewise-Koszul algebras with arbitrary “period” and piecewise-Koszul algebras with arbitrary “jump-degree”.