Commutative Schur Rings of Maximal Dimension

A commutative Schur ring over a finite group G has dimension at most s _G  = d ₁ + … +d _r , where the d _i are the degrees of the irreducible characters of G. We find families of groups that have S-rings that realize this bound, including the groups SL(2, 2 ⁿ ), metacyclic groups, extraspecial groups, and groups all of whose character degrees are 1 or a fixed prime. We also give families of groups that do not realize this bound. We show that the class of groups that have S-rings that realize this bound is invariant under taking quotients. We also show how such S-rings determine a random walk on the group and how the generating function for such a random walk can be calculated using the group determinant.     

Strong Cleanness of Matrix Rings Over Commutative Rings

Let R be a commutative local ring. It is proved that R is Henselian if and only if each R-algebra which is a direct limit of module finite R-algebras is strongly clean. So, the matrix ring 𝕄 _n (R) is strongly clean for each integer n > 0 if R is Henselian and we show that the converse holds if either the residue class field of R is algebraically closed or R is an integrally closed domain or R is a valuation ring. It is also shown that each R-algebra which is locally a direct limit of module-finite algebras, is strongly clean if R is a π-regular commutative ring.     

交换环上全矩阵代数的迹恒等式

本文研究了交换环上全矩阵代数的迹恒等式，特别研究了积的迹为零的多项式．     

Commutative Subalgebras of Quantum Algebras

In the present paper, a general assertion is proved, claiming that, for every associative algebra $\mathcal{A}$ without zero divisors which admits a valuation and a seminorm concordant with the valuation, the transcendence degree of an arbitrary commutative subalgebra does not exceed the maximal number of independent pairwise pseudocommuting elements of some basis of the algebra $\mathcal{A}$ . The author shows that for such a algebra $\mathcal{A}$ one can take an arbitrary algebra of quantum Laurent polynomials, quantum analogs of the Weyl algebra, and also some universal coacting algebras. In the case of the algebra $\mathcal{L}$ of quantum Laurent polynomials, it is proved that the transcendence degree of a maximal commutative subalgebra of $\mathcal{L}$ coincides with the maximal number of independent pairwise commuting elements of the monomial basis of the algebra $\mathcal{L}$ .     

Large Commutative Subalgebras of Quantum Algebras

In this paper, large commutative subalgebras of quantum algebras (in particular, quantum polynomial, matrix, and Weyl algebras) are studied. The notions of the transcendence degree and the Krull dimension are discussed. __________ Translated from Sovremennaya Matematika i Ee Prilozheniya (Contemporary Mathematics and Its Applications), Vol. 18, Algebra, 2004.     

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.     

交换环上Rao正则矩阵的广义Cramer法则

Gong Z,Aldeen M和Elsner L在[A note on a generalized Cramer’s rule,Linear AlgebraApp.,2002,340:253-254]中给出结论:对任意的k,α∈Qk,n,β∈Qk,m有|Xα,β|=|A-1|AYαβ,其中A∈n×n可逆矩阵,AX=Y.本文给出交换环上Rao正则矩阵的广义Cramer法则.     

可换环上上三角矩阵代数的若当自同构分解

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.     

矩阵环中的一类极大的广义的Armendariz子环

An associative ring with identity R is called Armendariz if, whenever （∑^m i=0^aix^i）（∑^n j=0^bjx^j）=0 in R[x],aibj=0 for all i and j. An associative ring with identity is called reduced if it has no non-zero nilpotent elements. In this paper, we define a general reduced ring （with or without identity） and a general Armendariz ring （with or without identity）, and identify a class of maximal general Armendariz subrings of matrix rings over general reduced rings.     

矩阵环中的基于幺半群的极大的Armendariz子环

Let M be a monoid. Maximal M-Armendariz subrings of upper triangular matrix rings are identified when R is M-Armendariz and reduced. Consequently, new families of M- Armendariz rings are presented.     

On the Dimensions of Commutative Subalgebras and Subgroups of Nilpotent Algebras and Lie Groups of Class 2

We obtain the functions that bound the dimensions of finite dimensional nilpotent associative or Lie algebras of class 2 over an algebraically closed field in terms of the dimensions of their commutative subalgebras. As a result, we also compute a similar function for complex nilpotent Lie groups of class 2.     

可换环上矩阵代数的SZ-导子, PZ-导子 和 S-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 with the usual product operation. An R-linear map φ ： Nn（R） → Nn（R） is said to be an SZ-derivation of Nn（R） if x2 = 0 implies that φ（x）x＋xφ（x） = 0. It is said to be an S-derivation of Nn（R） if φ（x2） = φ（x）x＋xφ（x） for any x ∈ Nn（R）. It is said to be a PZ-derivation of Nn（R） if xy = 0 implies that φ（x）y＋xφ（y） = 0. In this paper, by constructing several types of standard SZ-derivations of Nn（R）, we first characterize all SZ-derivations of Nn（R）. Then, as its application, we determine all S-derivations and PZ- derivations of Nn（R）, respectively.     

交换环上上三角矩阵代数在全矩阵代数中的扩代数及其若当导子

设R是任意含么交换环,2是R的可逆元.M(n,R)表示R上所有n×n级矩阵形成的代数,T(n,R)表示R上所有n×n级上三角矩阵形成的代数.决定了T(n,R)在M(n,R)中的扩代数,并具体刻画了这些扩代数的若当导子.     

交换环上全矩阵代数迹恒等式的几个定理

本文研究了交换环上全矩阵代数的迹恒等式，特别研究了积的迹为零的多项式，它好比矩阵或多项式正交，在现代物理学中有着十分广泛的应用．     

Decomposition of Jordan Automorphisms of Strictly Upper Triangular Matrix Algebra Over Commutative Rings

Over a 2-torsionfree commutative ring R with identity, the algebra of all strictly upper triangular n + 1 by n + 1 matrices is denoted by n ₁. In this article, we prove that any Jordan automorphism of n ₁ can be uniquely decomposed as a product of a graph automorphism, a diagonal automorphism, a central automorphism and an inner automorphism for n ≥ 3. In the cases n = 1, 2, we also give a decomposition for any Jordan automorphism of n ₁.     

Prime Lie Rings of Derivations of Commutative Rings

Let R be a 2-torsion free commutative ring with identity, and δ a nonzero derivation of R such that R is δ-prime. Then Rδ is a prime Lie ring and any nonzero ideal of Rδ contains an ideal of the form Jδ where J is a nonzero δ-ideal of R.