特征数p的代数闭域上不可约概齐次空间的分类(Ⅰ)

当基域K是特征数p>2的代数闭域时,本文给出了满足条件dimG≥dimV的不可约被约三元组的分类。为以后的不可约概齐次向量空间的分类作好准备。由于不可约表示的Weyl维数公式不再适用,因此我们利用在Weyl群作用下的权轨道对不可约模的维数作出估计。最后还得到了3个在特征数0的情形并不存在的新类:即(GL(n),(1+p~s)∧_1,∨(n~2))(s>0,n≥2),(GL(n),∧_1+p~s∧_(n-1),V(n~2))(s>0,n≥3)及(GL(4),∧_1+∧_2,V(16))(p=3)。     

非交换群上一类代数的不可约表示

在一类无限维非交换Hopf代数上,借助其Hopf理想,构造出商Hopf代数,讨论了此商代数上的有限维不可约模,得出此非平凡不可约模的维数一定是2.     

特征数p的代数闭域上不可约概齐次空间的分类(Ⅰ)

当基域 K 是特征数 p>2的代数闭域时,本文给出了满足条件 dimG≥dim V 的不可约被约三元组的分类.为以后的不可约概齐次向量空间的分类作好准备.由于不可约表示的 Weyl维数公式不再适用,因此我们利用在 Weyl 群作用下的权轨道对不可约模的维数作出估计.最后还得到了3个在特征数0的情形并不存在的新类:即(GL(n),(1+p~8)Δ_1,V(n~2))(s>0),n≥2),(GL(n),∧_1+ρ~3∧_(n-1),V(n~2))(s>0,n≥3)及(GL(4),∧_1+∧_2,V(16))(p=3).     

Ginzburg—Landau—Newell模型的动力学行为

本文对Ｇｉｎｚｂｕｒｇ－Ｌａｎｄａｕ－Ｎｅｗｅｌｌ模型的动力学行为进行了讨论，得到了该模型的整体吸引子的存在性，同时得到了此吸引子维数的下界估计和该吸引子的Ｈａｕｓｄｏｒｆｆ维数和Ｆｒａｃｔａｌ维数的上界估计。     

空间离散Fitz-Hugh-Nagumo方程和双稳反应扩散方程组的渐近行为

本文利用扰动方法,研究了Ｆitz-Hugh-Ngaumo方程和双稳反应扩散方程在Neuman边值条件下空间离散后的渐近行为,证明了两个格微分方程组的不变区域、吸引集和整体吸引子的存在性,并给出了离散Ｆitz-Hugh-Ngaumo方程的整体吸引子的Hausdorff维数估计。     

关于Witt代数基本子代数的一点注记

设g=W_1是特征p3的代数闭域k上的Witt代数.本文确定了g的极大基本子代数.进一步具体给出了最大维数的基本子代数的G共轭类,这里G是g的自同构群.从而证明了最大维数为(p-1)/2的基本子代数射影簇E((p-1)/2,g)是不可约的且是一维的.更进一步,证明了E(1,g)是不可约的,具有维数p-2,而E(2,g)是等维的,共有(p-3)/2个不可约分支,且每个不可约分支的维数是p-4.而当3≤r≤(p-3)/2时,E(r,g)是可约的.给出了E(r,g)(3≤r≤(p-3)/2)维数的一个下界.     

素特征的“李定理”

设L为代数闭域F上有限维李代数,著名的李定理说:若char F=0,则L为可解当且仅当L的任一有限维不可约模为1维的.在这里特征为0及模为有限维两个条件都是本质的.(1)若charF=P>0,则L为交换当且仅当L的任一(有限维)不可约模为1维的;(2)若char F=0,则L为交换当且仅当L的任一(有限维或无限维)不可约模为1维的; (3)若char F=P>7,L为李代数(限制李代数),则L为可解当且仅当L的任一不可约模(限制模)的维数为p的幂.     

素特征的"李定理"

设L为代数闭域F上有限维李代数,著名的李定理说若char F=0,则L为可解当且仅当L的任一有限维不可约模为1维的.在这里特征为0及模为有限维两个条件都是本质的.(1)若charF=p＞o,则L为交换当且仅当L的任一(有限维)不可约模为1维的;(2)若char F=0,则L为交换当且仅当L的任一(有限维或无限维)不可约模为1维的;(3)若charF=p＞7,L为李代数(限制李代数),则L为可解当且仅当L的任一不可约模(限制模)的维数为p的幂.     

非负循环矩阵的不可约性判定

利用关联矩阵,本文给出了关于非负循环矩阵不可约性及本原性的若干结果。     

环与剩余类环的同调维数

Ｓａｎｄｏｍｉｅｒｓｋｉ Ｆ．Ｌ,Ｓｍａｌｌ Ｌ．Ｗ,和 Ｆｉｅｌｄｓ Ｋ．Ｌ．［１－２］在“幂零”条件下研究了环与约化环的同调维数．然而对一些环（如交换 Ｖｏｎ Ｎｅｕｍａｎｎ正则环）,“幂零’的条件是不成立的．因此,在本文中我们考虑非“幂零”条件下（如Ｒ（Ｒ／Ｉ）（（Ｒ／Ｉ）Ｒ）是Ｒ－投身的或Ｒ（Ｒ／Ｉ）Ｒ是Ｒ－平坦的）,环与约化环的同调维数．     

Character and dimension formulae for general linear superalgebra

The generalized Kazhdan-Lusztig polynomials for the finite dimensional irreducible representations of the general linear superalgebra are computed explicitly. The result is then applied to prove a conjectural character formula put forward by van der Jeugt et al. in the late 80s. We simplify this character formula to cast it into the Kac-Weyl form, and derive from it a closed formula for the dimension of any finite dimensional irreducible representation of the general linear superalgebra.     

REMARKS ON BRUALDI＇S THEOREM FOR SPECTRUM INCLUSION REGION OF AN IRREDUCIBLE MATRIX

This paper obtains a necessary and sufficient condition for an irreducible complex matrix whose comparison matrix is a singular M-matrix to be singular. This is used to establish a necessary and sufficient condition for a boundary point of Brualdi‘s inclusion region of the eigenvalues of an irreducible complex matrix to be an eigenvalue.     

Multiplicity formulas for finite dimensional and generalized principal series representations

The article presents two results. (1) Let a be a reductive Lie algebra over ℂ and let b be a reductive subalgebra of a. The first result gives the formula for multiplicity with which a finite dimensional irreducible representation of b appears in a given finite dimensional irreducible representation of a in a general situation. This generalizes a known theorem due to Kostant in a special case. (2) LetG be a connected real semisimple Lie group andK a maximal compact subgroup ofG. The second result is a formula for multiplicity with which an irreducible representation ofK occurs in a generalized representation ofG arising not necessarily from fundamental Cartan subgroup ofG. This generalizes a result due to Enright and Wallach in a fundamental case.     

PARTITIONS OF SINGLE EXTERIOR TYPE

We characterize the irreducible representations of the general linear group GL(V) that have multiplicity 1 in the direct sum of all Schur modules of a given exterior power of V. These have come up in connection with the relations of the lower order minors of a generic matrix. We show that the minimal relations conjectured by Bruns, Conca and Varbaro are exactly those coming from partitions of single exterior type.     

Necklaces,symmetries and self-reciprocal polynomials

The connection between a certain class of necklaces and self-reciprocal polynomials over finite fields is shown. For n?2, self-reciprocal polynomials of degree 2n arising from monic irreducible polynomials of degree n are shown to be either irreducible or the product or two irreducible factors which are necessarily reciprocal polynomials. Using DeBruijn's method we count the number of necklaces in this class and hence obtain a formula for the number of irreducible self-reciprocal polynomials showing that they exist for every even degree. Thus every extension of a finite field of even degree can be obtained by adjoining a root of an irreducible self-reciprocal polynomial.     

关于非负不可约矩阵的广义Perron补的一些性质

1989年Meyer为计算马尔可夫链的平稳分布向量构造了一个算法，首次提出非负不可约矩阵的Perron补的概念。本文给出非负不可约矩阵A的广义Perron补若干性质，并且证明当矩阵A是不可约逆M-矩阵，其广义Perron补也是不可约逆M-矩阵。     

The minimal polynomial of a matrix

Let Rbe a finite dimensional central simple algebra over a field FA be any n× n matrix over R. By using the method of matrix representation, this paper obtains the structure formula of the minimal polynomial q_A(λ) of A over F. By using q_A(λ), this paper discusses the structure of right (left) eigenvalues set of A, and obtains the necessary and sufficient condition that a matrix over a finite dimensional central division algebra is similar to a diagonal matrix.     

The Hurwitz determinants and the signatures of irreducible representations of simple real Lie algebras

The paper deals with the real classical Lie algebras and their finite dimensional irreducible representations. Signature formulae for Hermitian forms invariant relative to these representations are considered. It is possible to associate with the irreducible representation a Hurwitz matrix of special kind. So the calculation of the signatures is reduced to the calculation of Hurwitz determinants. Hence it is possible to use the Routh algorithm for the calculation.     

An explicit Lipschitz constant for the joint spectral radius

In 2002, Wirth has proved that the joint spectral radius of irreducible compact sets of matrices is locally Lipschitz continuous as a function of the matrix set. In the paper, an explicit formula for the related Lipschitz constant is obtained.     

Tensor products of direct sums

A similar formula to the one established by Ansemil and Floret for symmetric tensor products of direct sums is proved for alternating and Jacobian tensor products. It is then applied to stable spaces where a number of isomorphisms between spaces of tensors or multilinear forms are unveiled. A connection between these problems and irreducible group representations is made.