k-Commuting maps on triangular algebras

In this paper, k-commuting maps on certain triangular algebras are determined. As an application we show that every k-commuting map on an upper triangular matrix algebra over a unital commutative ring of 2-torsion free or a nest algebra is proper.     

可换环上一些上三角矩阵李代数的导子

设R是任意含单位元的可换环,t是R上n×n上三角矩阵组成的李代数,b是R上迹为零的n×n上三角矩阵组成的李代数,本文明确给出了t和b的导子代数.     

可换环上一些线性李代数的扩代数

设R是任意含单位元的可换环,gl(n,R)是R上n级一般线性李代数.t表示gl(n,R)中所有上三角矩阵组成的子代数,d表示gl(n,R)中所有对角矩阵组成的子代数.本文将分别确定t在gl(n,R)中的扩代数和d在t中的扩代数.     

Lie products in incidence algebras

We give conditions when a strictly upper triangular element of an incidence algebra over a commutative ring is the Lie commutator of two elements of the incidence algebra, one of which is strictly upper triangular. In particular, it follows that this is the case for the ring of n × n upper triangular matrices, where n is either finite or infinite.     

保持交换环上两类矩阵运算的映射

主要针对交换环上两类矩阵的保持问题进行展开:(1)刻画了交换环上全矩阵空间和上三角形矩阵空间的保持反对合矩阵映射的形式.(2)研究了交换环上n阶上三角形矩阵空间的保持伴随矩阵映射的形式.     

The length function and matrix algebras

By the length of a finite system of generators for a finite-dimensional associative algebra over an arbitrary field we mean the least positive integer k such that words of length not exceeding k span this algebra (as a vector space). The maximum length for the systems of generators of an algebra is referred to as the length of the algebra. In the present paper, we study the main ring-theoretical properties of the length function: the behavior of the length under unity adjunction, direct sum of algebras, passage to subalgebras and homomorphic images. We give an upper bound for the length of the algebra as a function of the nilpotency index of its Jacobson radical and the length of the quotient algebra. We also provide examples of length computation for certain algebras, in particular, for the following classical matrix subalgebras: the algebra of upper triangular matrices, the algebra of diagonal matrices, the Schur algebra, Courter’s algebra, and for the classes of local and commutative algebras.     

Generalized Jordan derivations on triangular matrix algebras

In this note, we prove that every generalized Jordan derivation from the algebra of all upper triangular matrices over a commutative ring with identity into its bimodule is the sum of a generalized derivation and an antiderivation.     

Additivity of Jordan maps on triangular algebras

The aim of this article is to prove a result on the additivity of Jordan maps on triangular algebras. As a consequence the additivity of Jordan maps on upper triangular matrix algebras over a faithful commutative ring of 2-torsion free is determined.     

三角代数上的广义Jordan导子

主要研究了三角代数上的广义Jordan导子．利用三角代数上广义Jordan导子和广义内导子的联系．证明了作用在一个含单位元的可交换环上的三角代数到其自身上的环线性广义Jordan导子是一个广义导子．     

Good Gradings on Upper Block Triangular Matrix Algebras

We investigate group gradings of upper block triangular matrix algebras over a field such that all the matrix units lying there are homogeneous elements. We describe these gradings as endomorphism algebras of graded flags and classify them as orbits of a certain biaction of a Young subgroup and the group G on the set G ⁿ , where G is the grading group and n is the size of the matrix algebra. In particular, the results apply to algebras of upper triangular matrices.     

交换环上矩阵代数的局部化导子

Let R be a commutative ring with identity, Nn（R） the matrix algebra consisting of all n × n strictly upper triangular matrices over R. Several types of proper local derivations of Nn（R） （n ≤ 4） are constructed, based on which all local derivations of Nn（R） （n ≤ 4） are characterized when R is a domain.     

双模问题rad~t(-,-)与拟遗传代数

设 Ｂ是 Ｋｒｕｌｌ－ｓｃｈｍｉｄｔ范畴 Ｋ上的一个上三角双模，Ｂｒｕｓｔｌｅ和 Ｈｉｌｌｅ证明了Ｂ的矩阵范畴ｍａｔＢ的投射生成子Ｐ的自同态代数的反代数Ａ是拟遗传代数，而且代数Ａ的△－好模范畴与ｍａｔＢ等价．本文把这些结果推广到由Ｃｒａｗｌｅｙ-Ｂｏｅｖｅｙ给出的具有非零导子的双模上，并在此基础上着重讨论了遗传代数 的投射模范畴Ｐｒｏｊ上的双模ｒａｄｔ（－，－），刻画了它所对应的拟遗传代数的Ｇａｂｒｉｅｌ箭图与关系，以及它们的特征模和Ｒｉｎｇｅｌ对偶．     

交换环上严格上三角矩阵的广义李三导子(英文)

本文研究了交换环R上所有n×n严格上三角矩阵构成的李代数N(n,R)(n≥5)上广义李三导子.利用矩阵技巧,证明了N(n,R)(n≥5)上任意广义李三导子为一李三导子与一位似映射的和.对于N(n,R)(n≥3)上广义李导子,得出类似结果.     

可换环上上三角矩阵代数的若当自同构分解(英文)

设R是含单位元1和可逆元2的可换环,Tn+1(R)表示R上(n+1)×(n+1)级上三角矩阵全体所形成的矩阵代数.本文证明了T(R)的每一个若当自同构都可唯一的分解为图自同构,内自同构和对角自同构的乘积.     

Tracial algebras and an embedding theorem

We prove that every positive trace on a countably generated ∗-algebra can be approximated by positive traces on algebras of generic matrices. This implies that every countably generated tracial ∗-algebra can be embedded into a metric ultraproduct of generic matrix algebras. As a particular consequence, every finite von Neumann algebra with separable pre-dual can be embedded into an ultraproduct of tracial ∗-algebras, which as ∗-algebras embed into a matrix-ring over a commutative algebra.     

Hadamard algebras possessing the unique noncommutative simple component

The famous conjecture on the orders of Hadamard matrices can be reformulated as follows: a commutative algebra is Hadamard if and only if its dimension is divisible by 4. In this paper we study the Hadamard algebras closed to commutative ones, namely, the algebras possessing the unique noncommutative simple component being the matrix algebra of order 2.     

Involutions for upper triangular matrix algebras

In this paper we describe completely the involutions of the first kind of the algebra UT_n(F) of n×n upper triangular matrices. Every such involution can be extended uniquely to an involution on the full matrix algebra. We describe the equivalence classes of involutions on the upper triangular matrices. There are two distinct classes for UT_n(F) when n is even and a single class in the odd case.Furthermore we consider the algebra UT₂(F) of the 2×2 upper triangular matrices over an infinite field F of characteristic different from 2. For every involution *, we describe the *-polynomial identities for this algebra. We exhibit bases of the corresponding ideals of identities with involution, and compute the Hilbert (or Poincaré) series and the codimension sequences of the respective relatively free algebras.Then we consider the *-polynomial identities for the algebra UT₃(F) over a field of characteristic zero. We describe a finite generating set of the ideal of *-identities for this algebra. These generators are quite a few, and their degrees are relatively large. It seems to us that the problem of describing the *-identities for the algebra UT_n(F) of the n×n upper triangular matrices may be much more complicated than in the case of ordinary polynomial identities.