GICAR代数中的闭Lie理想

本文给出了GICAR代数中闭Lie理想的完全刻画.设A是GICAR代数,L是A的闭Lie理想,则存在A的闭理想J,使得[A,J]=[J,J](?) L (?) π-1(Z(A/J)),其中π是A到A/J上的商映射.反之,任意这种形式的闭子空间L是A的闭Lie理想.     

投射模的自同态代数与有限维猜想北大核心CSCD

设代数A是整体维数有限的Artin代数,e是A的一个幂等元,则e Ae的有限维数有限,如果以下条件满足其一:(a)rep.dim(A/Ae A)≤3,且对任意单A/Ae A-模K,有proj.dim(AK)≤4;(b)对任意单A/Ae A-模K,都有proj.dim(AK)≤3.     

连通微分分次代数的整体维数

首次把有理同伦论中的同伦不变量-锥长度(cone length)引入到微分分次(简记为DG)同调代数中,定义了连通DG代数上DG模的锥长度.连通DG代数A的左(右)整体维数定义为所有DGA-模(Aop-模)的锥长度的上确界.在一些特殊情形下,发现连通.DG代数A的左(右)整体维数与H(A)的整体维数有着密切的关系.任意一个连通分次代数,如果将它视为微分为O的连通DG代数,其左(右)整体维数与其作为连通分次代数的整体维数是一致的.因此该定义是连通分次代数整体维数的一种推广形式.证明A的整体维数足三角范畴D(A)以及Dc(A)的维数的一个上界.当A是正则DG代数时,给出了A的左(右)整体维数的一个有限上界.     

李代数$W(2,2)$上的Poisson结构

Poisson代数是指同时具有代数结构和李代数结构的一类代数,其乘法和李代数乘法满足Leibniz法则.李代数W(2,2)在权为2的向量生成的顶点算子代数的分类中起着重要作用.文章主要确定了李代数W(2,2)上的Poisson结构,并得到了Virasoro代数上一般的非结合的Poisson结构,改进了文[姚裕丰.Witt代数和Virasoro代数上的Poisson代数结构[J].数学年刊,2013,34A(1):111-128]的部分结果.     

广义分段Koszul代数

广义分段Koszul代数(简称为K_p代数)一般是一类二次代数,其平凡模允许有非单纯的投射分解.利用Yoneda-Ext代数E(A)给出了分次代数A是K_p代数的一个充分条件,同时讨论了K_p代数的商代数是否继承K_p性质.     

Jordan代数上的可乘Jordan导子

设A是Jordan代数,如果映射d:A→A满足任给a,b∈A,都有d(aob)=d(a)o b+aod(b),则称d为可乘Jordan导子.如果A含有一个非平凡幂等p,且A对于p的Peirce分解A=A_1⊕A_(1/2)⊕A_0满足:(1)设ai∈Ai(i=1,0),如果任给t_(1/2)∈A_(1/2),都有a_i○t_(1/2)=0,则a_i=0,则A上的可乘Jordan导子d.如果满足d(p)=0,则d是可加的.由此得到结合代数和三角代数满足一定条件时,其上的任意可乘Jordan导子是可加的.     

广义分段Koszul代数

广义分段Koszul代数(简称为κ_p代数)一般是一类二次代数,其平凡模允许有非单纯的投射分解.利用Yoneda-Ext代数E(A)给出了分次代数A是κ_p代数的一个充分条件,同时讨论了κ_p代数的商代数是否继承κ_p性质.     

Smash积的复杂度

给定任意一个有限维代数A,记其复杂度为C（A）.本文的主要结果是：如果有限维Hopf代数H和H是半单的,则对任意有限维H-模代数A,有C（A#H）=C（A）.利用此等式,可以计算一些代数的复杂度.     

紧致DG模和Gorenstein DG代数

证明同调有界的连通微分分次代数（简称为DG代数）上的紧致DG模的ampli-tude与基代数的amplitude的差恰为该DG模的投射维数.由此可得非平凡的正则DG代数是同调无界的.对正则DG代数A,若它的同调代数H（A）是分次Koszul代数,则证明H（A）有有限的整体维数;如果把条件减弱为A是Koszul DG代数,则给出了一个H（A）的整体维数为无限的例子.对一般的正则DG代数A,给出了其为Gorenstein DG代数的一些等价刻画.对同调有限维的连通DG代数A,证明由紧致对象全体构成的三角范畴Dc（A）和Dc（Aop）存在Auslander-Reiten三角当且仅当A和Aop都是Gorenstein DG代数.当A是非平凡的正则DG代数,且H（A）是局部有限维时,Dc（A）不存在Auslander-Reiten三角.对正则DG代数A,转而讨论了Auslander-Reiten三角在Dlbf（A）以及Dlbf（Aop）上的存在性.     

逆步李代数g(A)的导子代数

本文对逆步李代数g(A)的导子代数进行了研究.这里A是任意一个n×n阶的复矩阵,而g(A)是和其相关联的逆步李代数.特别地,当A是广义Caftan矩阵时, g(A)则为Kac-Moody代数.在这里,我们得到了g(A)的导子代数的结构.     

集对代数与3值代数

研究集对代数 ,证明每个 3值代数同构于某个集对代数的子代数 ,从而推广文 [3]的结论 ,并讨论集对代数的直积分解。     

Matrix Algebras and Reality-Based Algebras

We describe the distinguished bases of M ₂(?) as a Core Structure, and then give a negative answer to Question 1.2 raised by Harvey I. Blau in [1 Blau , H. I. ( 2009 ). Table algebras . European J. Combin. 30 : 1426 – 1455 . [Google Scholar]].     

蕴涵代数与BCK代数

系统研究 Fuzzy蕴涵代数与 BCK代数之间的关系 ,给出 MV代数与 BCK代数之间的联系 ,建立正则 FI代数和对合 BCK代数的对偶代数     

Finite Left-Distributive Algebras and Embedding Algebras

We consider algebras with one binary operation · and one generator (monogenic) and satisfying the left distributive lawa·(b·c)=(a·b)·(a·c). One can define a sequence of finite left-distributive algebrasA_n, and then take a limit to get an infinite monogenic left-distributive algebraA_∞. Results of Laver and Steel assuming a strong large cardinal axiom imply thatA_∞is free; it is open whether the freeness ofA_∞can be proved without the large cardinal assumption, or even in Peano arithmetic. The main result of this paper is the equivalence of this problem with the existence of a certain algebra of increasing functions on natural numbers, called anembedding algebra. Using this and results of the first author, we conclude that the freeness ofA_∞is unprovable in primitive recursive arithmetic.     

Composition Algebras with Large Derivation Algebras

The finite dimensional flexible composition algebras include the Hurwitz algebras (composition algebras with unit element), but also other interesting classes of algebras: the para-Hurwitz and the Okubo algebras. The above mentioned algebras present many symmetries, and this is reflected in their large derivation algebras. In the present paper we study the opposite question: What can be said about the composition algebras if we have some information about their derivation algebras? Our main result is the classification of all the composition algebras with such large derivation algebras.     

How to Obtain Non-Flexible Quadratic Algebras as Mutation Algebras of Hurwitz Algebras

We present an elementary way to obtain new families of division algebras of degree n out of division algebras with a multiplicative norm. Families of four- and eight-dimensional non-flexible quadratic division algebras over a field F of characteristic not 2 are easily constructed as a-mutation algebras of Hurwitz division algebras A over F, choosing ${a \in A \setminus F}$ suitable. In particular, we thus obtain real eight-dimensional division algebras with large derivation algebras.     

Structure Theorems for Bicomodule Algebras Over Quasi-Hopf Algebras,Weak Hopf Algebras,and Braided Hopf Algebras

Let H be a quasi-Hopf algebra, a weak Hopf algebra, or a braided Hopf algebra. Let B be an H-bicomodule algebra such that there exists a morphism of H-bicomodule algebras v: H → B. Then we can define an object B^co(H), which is a left-left Yetter–Drinfeld module over H, having extra properties that allow to make a smash product B^co(H)#H, which is an H-bicomodule algebra, isomorphic to B.