分块算子矩阵闭值域研究

主要研究分块算子矩阵值域的闭性问题.运用扰动理论和Hyers-Ulam稳定性,给出分块算子矩阵值域为闭的充分条件.最后用一些例子说明判别准则的有效性.     

上三角算子矩阵的谱

设X,y是Banach空间,对A∈B(X),B∈B(y),C∈B(Y,X),以M_C记X⊕Y上的算子(ACOB).本文给出了算子M_C的20种谱的结构表示,18种谱的填洞性质以及关于这些问题的有趣例子.     

一般非均匀凸介质的迁移算子广义本征函数系统的完整性

该文讨论一般非均匀凸介质所确定的迁移算子的广义本征函数系统的完整性问题，利用我们探索的相对收敛方法，完整地刻划了一般非均匀凸介质中迁移问题的广义本征函数系统的完整性问题，我们证明了，对迁移半群E（t），当0∈Pσ（E（t）），迁移算子广义本征函数系统不完整，当0∈Pσ（E（t））时，仅当满足相对收敛条件时，迁移算子的广义本征函数系统完整．     

一类缺项算子矩阵的谱扰动

有界线性算子的点谱和剩余谱分别可进-步细分为两类:σ_(p1),σ_(p2)和σ_(r1),σ_(r2).设H,K为无穷维可分的Hilbert空间,本文将对于给定的A ∈B (H),B ∈B(K),给出了缺项算子M_C=(AC/OB)关于分类后所得四种谱的扰动结果.     

The Spectral Shift Function for Certain Block Operator Matrices

Let L₀ be a 2 × 2 diagonal self‐adjoint block operator matrix with entries A and D. If operators B and B* are added to the off diagonal zeros, certain parts of the spectrum of L₀ move to the right and other parts move to the left. In this paper it is shown that, correspondingly, if B is a trace class operator M. G. Krein's spectral shift function is of constant sign on certain intervals.     

2×2上三角算子矩阵的左(右)Weyl谱的交

本文刻画了上三角算子矩阵M_C=(A0CB)■→■左(右)Weyl谱的交.     

缺项算子矩阵的本性谱

Let =(A C X B)be a 2×2 operator matrix acting on the Hilbert space н( )κ.For given A ∈B (H),B ∈B(K)and C ∈B(K,H)the set Ux∈B(H,к)σe(Mx)is determined,where σe(T)denotes the essential spectrum.     

分块算子矩阵的加权EP

本文在加权广义Schur补的基础上, 引入并研究了Hilbert空间上分块算子矩阵的加权Moore-Penrose逆和加权EP. 进一步, 给出了加权EP算子在算子方程中的一个应用.     

On eigenfunction expansions of piecewise smooth functions,associated with the power of the Schrödinger operator

The eigenfunction expansions of an integer power of the Schrödinger operator in an arbitrary two-dimensional domain are considered. The convergence of the corresponding expansions of piecewise smooth functions is proved. When the dimension of the domain is greater than two, then it is well known that this result is not valid any more.     

Operator Interpretation of Resonances Arising in Spectral Problems for 2 × 2 Operator Matrices

We consider operator matrices ${\rm{H = }}\left( {{_{B_{10} }^{A{_0}}} {_{A_{1} }^{B{_{01}}}} } \right)$ with self - adjoint entries A_i, i = 0,1, and bounded B₁₀ = B₁₀ acting in the orthogonal sum μ=μ₀ ⊕ μ₁ of Hilbert spaces μ₀ and μ₁. We are especially interested in the case where the spectrum of, say, A₁ is partly or totally embedded into the continuous spectrum of A₀ and the transfer function V₁(z) = B₁₀ where (χ - A₀)^?1 B₀₁, admits analytic continuation (as an operator - valued function) through the cuts along branches of the continuous spectrum of the entry A₀ into the unphysical sheet(s) of the spectral parameter plane. The values of χ in the unphysical sheets where M₁^?1(z) and consequently the resolvent (H - z)^?1 have poles are usually called resonances. A main goal of the present work is to find non - selfadjoint operators whose spectra include the resonances as well as to study the completeness and basis properties of the resonance eigenvectors of M₁(z) in μ₁. To this end we first construct an operator - valued function V₁(Y) on the space of operators in μ₁ possessing the property: V₁(Y)?₁ = V₁(z)?₁ for any eigenvector ?₁ of Y corresponding to an eigenvalue z and then study the equation H₁ = A₁ + V₁(H₁). We prove the solvability of this equation even in the case where the spectra of A₀ and A₁ overlap. Using the fact that the root vectors of the solutions H₁ are at the same time such vectors for M₁(z), we prove completeness and even basis properties for the root vectors (including those for the resonances).     

Simplicity of a Vertex Operator Algebra Whose Griess Algebra is the Jordan Algebra of Symmetric Matrices

Let r ∈ ? be a complex number, and d ∈ ?_≥2 a positive integer greater than or equal to 2. Ashihara and Miyamoto [4 Ashihara , T. , Miyamoto , M. ( 2009 ). Deformation of central charges, vertex operator algebras whose Griess algebras are Jordan algebras . Journal of Algebra 32 : 1593 – 1599 . [Google Scholar]] introduced a vertex operator algebra V _𝒥 of central charge dr, whose Griess algebra is isomorphic to the simple Jordan algebra of symmetric matrices of size d. In this article, we prove that the vertex operator algebra V _𝒥 is simple if and only if r is not an integer. Further, in the case that r is an integer (i.e., V _𝒥 is not simple), we give a generator system of the maximal proper ideal I _r of the VOA V _𝒥 explicitly.     

有理对称矩阵的准正交相似

对一个有理对称矩阵A,用线性代数的理论直接证明了存在准正交矩阵P使得P~(-1)AP成为A的有理标准形,并给出了P的算法.     

Binary Representation of Normalized Symmetric and Correlation Matrices

With a view toward the correlation matrices, it is shown that the normalized real symmetric matrices are the affine hull of the binary correlation matrices, while the convex hull is a proper subset of the correlation matrices. A number of ways to identify the correlation matrices in the affine hull are discussed.     

Binary Representation of Normalized Symmetric and Correlation Matrices

With a view toward the correlation matrices, it is shown that the normalized real symmetric matrices are the affine hull of the binary correlation matrices, while the convex hull is a proper subset of the correlation matrices. A number of ways to identify the correlation matrices in the affine hull are discussed.     

正则Cosine算子函数的乘积扰动定理

本文研究了正则cosine算子函数的乘积扰动性,在正则化算子C的值域不 一定稠密的一般情形下,获得了若干正则cosine算子函数的乘积扰动定理.     

2×2算子矩阵的逆

设H和K为复的无限维可分Hilbert空间．本文利用算子的几何结构着重研究了Hilbert空间H(?)K上的2×2算子矩阵的逆,给出了一些有意义的结果．     

保持算子乘积谱函数的映射

设A和B为无限维复Banach空间上的标准算子代数,记Δ~R(·)为下列谱函数之一:σ~R(·),σ_l~R(·),σ_r~R(·),σ_l~R(·)∩σ_r~R(·),(?)σ~R(·),(?)σ~R(·),σ_p~R(·),σ_c~R(·),σ_(ap)~R(·),σ_s~R(·),σ_(ap)~R(·)∩σ_s~R(·),σ_p~R(·)∩σ_c~R(·),σ_p~R(·)∪σ_c~R(·),其中R=A或B.证明了A和B之间的每个保持算子Jordan三乘积(算子乘积)之谱函数△~R(·)的满射Φ必有形式Φ=(?)π,其中(?)是1的立方根(1的平方根)而π或者是A和B之间的代数同构,或者是代数反同构.也获得不定度规空间上的标准算子代数之间保持算子斜乘积之谱函数的映射的完全刻画.     

反对角算子矩阵及其平方的(ω)性质的摄动

设H为复的无限维可分的Hilbert空间,B(H)为H上的有界线性算子的全体.若σ_a(T)\σ_(ea)(T)=π_(00)(T),则称T∈B(H)满足(ω)性质,其中σ_a(T)和σ_(ea)(T)分别表示算子T的逼近点谱和本质逼近点谱,π_(00)(T)={λ∈isoσ(T):0dimN(T-λI)∞}.T∈B(H)称为满足(ω)性质的摄动,若对任意的紧算子K,T+K满足(ω)性质.本文证明了反对角算子矩阵及其平方具有(ω)性质的摄动的等价性.     

对称算子的两种自伴延拓形式之间的联系

考虑了von Neumann形式的自伴延拓和以Calkin方法给出的自伴延拓之间的关系，证明了这两种自伴延拓是一致的并可以互相转化的.     

Operator Matrix Forms of Positive Operators

If a 3-tuple (A:H1→H1,B:H2→H1,C:H2→H2）of operators on Hibert spaces is given,we proved that the operator ～↑A:=(↑A ↓B^*↑B ↓C) on H=H1 H2 is ≥0 is and only if A≥0,R(B)∪→R（A^1/2) and C≥B^* A^ b,where A^ is the generalized inverse of A.In general,A^ is a closed operator,but since R(B)∪→R(A^1/2,B^* A^ B is bounded yet.