2×2-上三角算子矩阵谱的Fredholm扰动

设H和K是复无穷维可分Hilbert空间,A∈B(H),B∈B(K),C∈B(K,H)且M_C=(ACOB).本文给出了上三角算子矩阵M_C的Weyl谱、本性谱、谱、左谱、右谱、下半本性谱、下半Weyl谱和上半Weyl谱的Fredholm扰动的完全刻画.     

上三角算子矩阵的左(右)本质谱的自伴扰动

设H为无穷维Hilbert复可分空间.对给定算子A ∈B(H)和B∈B(H),记MX:=[A0XB],其中X∈(F)(H)为自伴算子.本文首先给出了存在X ∈(F)(H),使得 Mx为左(右)Fredholm算子的充分必要条件.其次,证明了∩ σ*(MX)=∩ σ*(MX)U△,X∈(F)(H)X∈B(H)其中σ*是左...     

有界线性算子的摄动定理

本文研究了正则算子的摄动理论.考虑Banach空间X上的正则算子T,假设dim[K(T)∩N(T)]<∞且K(T)闭,则当S∈B(X)可逆,ST=TS,‖S‖充分小时,证明了T—S为上半Fredholm算子.在以上条件下,若K(T)+N(T)或者R(T)+N(T)在X中有有限维的补子空间,这时T—S为Fredholm算子.     

3×3上三角算子矩阵的Weyl型定理

设A∈B(H1),B∈B(H2),C∈B(H3)为给定的三个算子,用M(D,E,F)= 表示一个作用在H1(?)H2(?)H3上的3×3算子矩阵．本文首先给出存在算子D∈B(H2,H1),E∈B(H3,H1),F∈B(H3,H2),使得M(D,E,F)为上半Fredholm算子(下半Fredholm算子)的充要条件．同时研究了3×3算子矩阵 M(D,E,F)的Weyl定理,α-Weyl定理,Browder定理和α-Browder定理．     

算子矩阵值域的闭性及其应用

令{H}和{K}均为无限复可分的Hilbert空间. 定义M_X=(A&C\\X&B\)为作用在{H}}\oplus{K}上的2x2算子矩阵, 其中X为从{H}到{K}上未知的有界线性算子.在本文中, 基于R(C)的闭性对某个(或任意的)X\in{B}}({H,K}}), 使得R(M_{X})为闭集的充要条件做了等价刻画.另外, 研究了算子矩阵M_{X的半Fredholm性与广义Weyl性并给出了一些相应的结论.     

2×2上三角算子矩阵的Drazin谱

设MC=[A C 0 B]是从Hilbert空间H⊕K到H⊕K中的2×2上三角算子矩阵.该文主要研究MC的Drazin可逆性和MC的Drazin谱.此外,对给定算子A∈B(H)和B∈B(K),将给出在一定条件下所有上三角算子矩阵Mc的Drazin谱的交∩C∈B(K,K)σD(MC)的具体表达式.     

2x2上三角算子矩阵的左(右)Weyl谱的并集

设H,K为可分Hilbert空间,A E B(H),B ∈B(K)是给定的有界线性算子,定义Mc =(AC/OB).刻画了Mc的左Weyl谱(右Weyl谱,Weyl谱)的并集.     

广义Kato分解与Weyl型定理的摄动

称T∈B(H)有广义Kato分解,若存在一对T的闭的不变子空间(M,N)使得H=M⊕Ⅳ,其中T|_M为上半Fredholm算子且具有非负的指标,T|_N是幂零的本文利用算子的广义Kato分解性质,研究了Weyl型定理在紧摄动下的稳定性.此外还研究了2×2上三角算子矩阵的Weyl型定理在紧摄动下的稳定性.     

一类缺项算子矩阵的谱补问题

对于Hilbert空间上的2×2算子矩阵,其中A∈B（H）,C∈B（K,H）,D∈B（H,K）给定,当X取遍B（K）中算子时,我们给出所有Nx的谱之交集和并集的刻画．     

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.     

Characterization of types of asymptotic discernibility of families of hypotheses

We give a characterization of the types of asymptotic discernibility of families of hypotheses in the case of hypothetical measures that are not, in general, mutually absolutely continuous. The case when the logarithm of the likelihood ratio admits an asymptotic expansion of the type of an expansion with local asymptotic normality is examined in detail. Examples are studied.Translated fromTeoriya Sluchainykh Protsessov, Vol. 15, pp. 64–71, 1987.     

Estimates of stability of characterization of additive types of distributions

An estimate of stability of characterization of distribution types is obtained for the case of additive types. Under some conditions, the estimate has the order ε^1/3L(ε), where L(ε) is a slowly varying function. Proceedings of the Seminar on Stability Problems for Stochastic Models, Moscow, Russia, 1996, Part I.     

一类完全正则半群簇子簇格的性质

本文研究了完全正则半群簇的子簇格［Ｖ＋∩ＰＶ，Ｖ＋∩ＰＶ］的某些格运算性质，我们证明了簇Ｖ＋∩ＰＶ可分解为Ｖ与Ｖ＋∩ＰＶ的并；对任意完全正则半群簇Ｗ，有Ｗ∩（Ｖ∨Ｖ＋∩ＰＶ）＝（Ｗ∩Ｖ）∨（Ｗ∩Ｖ＋∩ＰＶ）．特别地，我们得到了等式Ｖ＋∩ＰＶ＝Ｖ成立的若干条件．     

Study of the blow-up of solutions of systems of equations of hydrodynamic type

Mathematical Notes - We study the initial boundary-value problem for three-dimensional systems of equations of pseudoparabolic type. The system is similar to the Oskolkov system, but differs from...     

Distribution of types of symmetry of tensors of high degree

The asymptotic distribution of tensors of degree N in symmetry types is studied in this paper.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 155, pp. 181–186, 1986.     

图表示范畴的两个子范畴

引进图表示范畴的两个子范畴,研究它们的同调性质。     

Emptiness of set of points of lower semicontinuity of Lyapunov exponents

We consider parametric families of differential systems with coefficients that are bounded and continuous on the half-line and uniformly in time continuously depend on a real parameter. For each Lyapunov exponent, we construct a family such that the Lyapunov exponent of its systems treated as a function of the parameter is not a lower semicontinuous function for any value of the parameter.