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161.
等变集压缩场的零点指标公式 总被引:4,自引:0,他引:4
本文在紧致李群作用下的Banach空间中,讨论了等变严格集压缩场的正则零点轨道的指标计算问题,推广了(1),(2)的结果。 相似文献
162.
王琪 《武汉大学学报(理学版)》2003,49(5):553-555
首先得到一个推广的Simons型积分不等式,然后用它给出共形平坦黎曼流形中紧致极小子流形对外围空间的一个拼挤定理. 相似文献
163.
Volker Runde 《Journal of Mathematical Analysis and Applications》2007,329(1):736-751
Let G be a locally compact group, and let R(G) denote the ring of subsets of G generated by the left cosets of open subsets of G. The Cohen-Host idempotent theorem asserts that a set lies in R(G) if and only if its indicator function is a coefficient function of a unitary representation of G on some Hilbert space. We prove related results for representations of G on certain Banach spaces. We apply our Cohen-Host type theorems to the study of the Figà-Talamanca-Herz algebras Ap(G) with p∈(1,∞). For arbitrary G, we characterize those closed ideals of Ap(G) that have an approximate identity bounded by 1 in terms of their hulls. Furthermore, we characterize those G such that Ap(G) is 1-amenable for some—and, equivalently, for all—p∈(1,∞): these are precisely the abelian groups. 相似文献
164.
Ming‐Chih Lai 《Numerical Methods for Partial Differential Equations》2004,20(1):72-81
In this article, we extend our previous work 3 for developing some fast Poisson solvers on 2D polar and spherical geometries to an elliptical domain. Instead of solving the equation in an irregular Cartesian geometry, we formulate the equation in elliptical coordinates. The solver relies on representing the solution as a truncated Fourier series, then solving the differential equations of Fourier coefficients by finite difference discretizations. Using a grid by shifting half mesh away from the pole and incorporating the derived numerical boundary value, the difficulty of coordinate singularity can be elevated easily. Unlike the case of 2D disk domain, the present difference equation for each Fourier mode is coupled with its conjugate mode through the numerical boundary value near the pole; thus, those two modes are solved simultaneously. Both second‐ and fourth‐order accurate schemes for Dirichlet and Neumann problems are presented. In particular, the fourth‐order accuracy can be achieved by a three‐point compact stencil which is in contrast to a five‐point long stencil for the disk case. © 2003 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 72–81, 2004 相似文献
165.
Stefan Bilbao 《Numerical Methods for Partial Differential Equations》2004,20(3):463-480
This article is devoted to an analysis of simple families of finite difference schemes for the wave equation. These families are dependent on several free parameters, and methods for obtaining stability bounds as a function of these parameters are discussed in detail. Access to explicit stability bounds such as those derived here may, it is hoped, lead to optimization techniques for so‐called spectral‐like methods, which are difference schemes dependent on many free parameters (and for which maximizing the order of accuracy may not be the defining criterion). Though the focus is on schemes for the wave equation in one dimension, the analysis techniques are extended to two dimensions; implicit schemes such as ADI methods are examined in detail. Numerical results are presented. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 463–480, 2004. 相似文献
166.
Jan Chabrowski 《Ricerche di matematica》2007,56(2):297-319
We consider the semilinear Neumann problem involving the critical Sobolev exponent with an indefinite weight function and
a concave purturbation. We prove the existence of two distinct solutions.
相似文献
167.
Sami Baraket Makkia Dammak Taieb Ouni Frank Pacard 《Annales de l'Institut Henri Poincaré (C) Analyse Non Linéaire》2007,24(6):875-895
Using some nonlinear domain decomposition method, we prove the existence of branches of solutions having singular limits for some 4-dimensional semilinear elliptic problem with exponential nonlinearity. 相似文献
168.
Aref Jeribi Hatem Megdiche Nedra Moalla 《Mathematical Methods in the Applied Sciences》2005,28(2):127-145
This paper deals with Rotenberg's models of cell populations with general boundary conditions. It is shown, first, that the associated Cauchy problem is governed by a C0‐semigroup. Second, we have proved that if the boundary operator is positive, the transport semigroup is irreducible. And finally, a spectral decomposition of the solution into an asymptotic term was derived. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
169.
M. Brokate 《Journal of Mathematical Analysis and Applications》2006,319(1):94-109
We consider hysteresis perturbations of a system of ODEs which possesses an asymptotically stable periodic solution z∗. Where the oscillation of an appropriate projection of this periodic solution is smaller than some threshold number defined by the hysteresis nonlinearity, it is shown that the perturbed system has a continuum of periodic solutions with a rather simple structure in a vicinity of z∗. The main result is a theorem on the stability of this continuum. 相似文献
170.
We find exact solutions of the equations of motion for a closed relativistic string that carries a point mass and moves in the space given by the direct product of Minkowski space and a compact manifold (multidimensional torus). We investigate physical characteristics of the system states described by these solutions.Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 142, No. 1, pp. 72–82, January, 2005. 相似文献