Criterion for Lagrange stability of a class of pendulum-like systems in Hilbert spaces

In this paper, a class of pendulum-like systems in infinite-dimensional Hilbert spaces is investigated. A frequency domain criterion guaranteeing the systems with the property of Lagrange stability is established.     

Well-posedness of general nonlocal nonhomogeneous boundary value problems for pseudodifferential equations with partial derivatives

In the article we study the questions of well-posedness of general nonlocal boundary value problems for pseudodifferential equations in the Besov-type limit spaces.     

Pontrjagin空间上算子集合的两个稠密性定理

Ｋａｐｌａｎｓｋｙ稠密性定理￣［１］是ｖｏｎＮｅｕｍａｎｎ代数和Ｃ￣＊代数理论中一个基本而重要的定理。算子代数中许多深刻的结果都是以此为工具导出的。要在不定度规空间上探讨算子代数的性质，人们自然会关心在这类空间上是否存在同一类型的结果。本文的主要目的就是在Ｐｏｎｔｒｊａｇｉｎ空间上给出一个相应的稠密性定理。同时，我们还将给出关于完全正则自共轭算子的另一个稠密性的结果。     

Banach空间中余弦算子函数生成元的有界性

A是Banach空间X中余弦算子函数C（t),t∈R，和正弦算子函数S（t),t∈R，的生成元。本证明了，对每个f∈C（[0,T];X)，连续函数u,u(t)=∫-tS(t-s)f(s)ds,f∈[0,T]是二阶非齐次0初值问题，u″=Au f的强解的充要条件是：A是空间X中的有界算子。     

Criterion for uniform invertibility of families of strong approximations to one-dimensional singular integral operators with continuous coefficients

A criterion is obtained for the applicability of the approximation method based on strongly approximating operator families converging to a one-dimensional singular integral operator with coefficients continuous in the circle. Some special cases are considered. Translated fromMatematischeskie Zametki, Vol. 62, No. 3, pp. 430–439, September, 1997. Translated by A. M. Chebotarev     

算子点态遍历定理

本文证明了关于Ｌ^P（１≤Ｐ≤∞）空间中线性算子与非线性算子的几个点态遍历定理，还推广了Ｙｏｓｉｄａ与ＫａＫｕｔａｎｉ关于拟紧算子的一致遍历定理。     

On certain spectral properties of a quadratic self-adjoint matrix pencil with dominating main diagonals

Sufficient conditions for the “separation of the spectrum” of a quadratic matrix pencil with self-adjoint coefficients are found. A criterion for the representability of a positive operator in a finite-dimensional space in the form of a matrix with dominating main diagonal in each orthonormal basis is obtained. Translated fromMatematicheskie Zametki, Vol. 61, No. 3, pp. 381–390, March, 1997. Translated by A. I. Shtern     

Quaternionic Killing Spinors

In [17] we proved a lower bound for the spectrum of the Dirac operator on quaternionic Kähler manifolds. In the present article we study the limiting case, i.e. manifolds where the lower bound is attained as an eigenvalue. We give an equivalent formulation in terms of a quaternionic Killing equation and show that the only symmetric quaternionic Kähler manifolds with smallest possible eigenvalue are the quaternionic projective spaces.     

A domain decomposition method for linear exterior boundary value problems

In this paper, we present a domain decomposition method, based on the general theory of Steklov-Poincaré operators, for a class of linear exterior boundary value problems arising in potential theory and heat conductivity. We first use a Dirichlet-to-Neumann mapping, derived from boundary integral equation methods, to transform the exterior problem into an equivalent mixed boundary value problem on a bounded domain. This domain is decomposed into a finite number of annular subregions, and the Dirichlet data on the interfaces is introduced as the unknown of the associated Steklov-Poincaré problem. This problem is solved with the Richardson method by introducing a Dirichlet-Robin-type preconditioner, which yields an iteration-by-subdomains algorithm well suited for parallel computations. The corresponding analysis for the finite element approximations and some numerical experiments are also provided.     

非线性RL电路的暂态特性

对一个可解的非线性ＲＬ电路模型的暂态过程进行了研究，得到非线性ＲＬ电路的一些普遍特性，加深了加ＲＬ电路中的有关概念的理解，对教学有一定的参考价值。