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991.
不变子空间问题的一个等价条件 总被引:1,自引:1,他引:0
本文得到了自反Banach空间X上有界线性算子全体所成的Banach代数的子代数的不变子空间问题的一个新的等价条件。 相似文献
992.
徐明跃 《数学的实践与认识》2004,34(6):172-176
首先给出 Banach空间为逼近紧的几何特征 .然后用随机变量组成的 Banach空间及空间中预报集的几何性质给出预报算子连续的条件 . 相似文献
993.
Stability of a class of linear transformations of distribution-valued stochastic processes is studied. Two types of applications to convergence of solutions of stochastic evolution equations are given. One of them, for the case of continuous limits, simplifies the tightness problem considerably due to a recent result of Aldous.Centro de Investigación y de Estudios Avanzados. 相似文献
994.
A. V. Balakrishnan 《Applied Mathematics and Optimization》1995,31(2):177-187
In this paper we generalize the Kalman-Yakubovic lemma to infinite dimensions—or, more precisely, to semigroups of operators over a Hilbert space. The proof differs substantially from the finite-dimensional version and is based on the Paley-Wiener-Helson-Lowdenslager factorization theorem. 相似文献
995.
Libor Veselý 《Czechoslovak Mathematical Journal》2002,52(4):721-729
We give a full characterization of the closed one-codimensional subspaces of c
0, in which every bounded set has a Chebyshev center. It turns out that one can consider equivalently only finite sets (even only three-point sets) in our case, but not in general. Such hyperplanes are exactly those which are either proximinal or norm-one complemented. 相似文献
996.
在单位多圆盘的Bergman空间上,本文分别刻画了以有界可测函数和有界多重调和函数为符号的本质交换对偶Toeplitz算子. 相似文献
997.
We investigate generating functions for equipped trees composed of double bonds of two sorts on a hypercubic lattice of dimension d with built-in fragments. Rules for constructing these clusters are chosen to ensure the estimate for coefficients of power series in time for the longitudinal and transverse autocorrelation functions of the spin system with axially symmetric interaction. We derive a system of two equations for the tree-generating functions and an equation for the generating functions of chains leading from the root to a fragment in a tree using the Bethe approximation and under the condition that mainly bonds of one sort are taken into account. For the face-centered hypercubic lattice, we find the first terms of the 1/d expansion for the coordinate of the singular point of the generating function in both the anisotropic and the isotropic cases taking fragments in the forms of a triangle from four bonds and a four-fold bound pair into account. The obtained result is written in terms of ratios of lattice sums and is generalized to nuclear spin systems with dipole–dipole interaction. The theoretical value of the singular-point coordinate agrees well with the experimental value calculated from the tail of the absorption spectrum of the nuclear magnetic resonance in a barium fluoride monocrystal. 相似文献
998.
Jürgen Appell 《Journal of Mathematical Analysis and Applications》2007,332(2):1134-1147
Using a continuation theorem for contractions, the existence, uniqueness, and an approximation method for a class of nonlinear boundary value problems on an unbounded interval is obtained. The results apply in particular to the problem in the title. 相似文献
999.
We show some Hyers-Ulam type stability results for some nonlinear recurrences in metric spaces. 相似文献
1000.
Stephan Ramon Garcia 《Journal of Mathematical Analysis and Applications》2007,335(2):941-947
If C is a conjugation (an isometric, conjugate-linear involution) on a separable complex Hilbert space H, then T∈B(H) is called C-symmetric if T=CT∗C. In this note we prove that each C-symmetric contraction T is the mean of two C-symmetric unitary operators. We discuss several corollaries and an application to the Friedrichs operator of a planar domain. 相似文献