摘要:

AbstractFor Ω an open subset of IRNand 1

ISSN:0025-584X    

DOI:10.1002/mana.19991970102

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

摘要:

AbstractGiven an orthonormal systemBin someL2(u) we consider the operator ideals IIBandTBofB‐summing andB‐type operators and some related ideals. We characterize by certain weak compactness properties when IIBis equal to the operator ideal II2of 2‐summing operators. In lose thatBconsists of characters of a compact abelian group we characterize when IIBcoincides with the operator ideal IIγof Gauss‐summing operators and whenTBcoincides with the operator ideal IIpof type‐2 operators. Moreover, we give a necessary and sufficient condition for Fig to contain the operator ideal IIpofp‐summing operators (2

ISSN:0025-584X    

DOI:10.1002/mana.19991970103

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

摘要:

AbstractIn a previous paper for a class of pairs of operators in a Hilbert space with nuclear difference or under a more general nuclearity condition there was introduced a spectral shift functional. Here we consider the local integrability of this spectral shift functional, i.e., the problem when this functional can locally be represented by an integrable function. The general results are then applied to pairs of definitizable and locally definitizable unitary operators in a Krein space.

ISSN:0025-584X    

DOI:10.1002/mana.19991970104

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

ISSN:0025-584X    

DOI:10.1002/mana.19991970105

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

摘要:

AbstractA bifurcation problem for the inequality\documentclass{article}\pagestyle{empty}\begin{document}$$\left\{ {\begin{array}{*{20}c} {U\left( t \right) \in K,} \\ {\left( {U\left( t \right) - A_\lambda U\left( t \right) - G\left( {\lambda,U\left( t \right)} \right),V - U\left( t \right)} \right) \ge 0\;{\rm{for}}\;{\rm{all}}\;V \in K,\;{\rm{a}}{\rm{.a}}{\rm{.}}\;t \in \left[ {0,T} \right]} \\ \end{array}} \right.$$\end{document}, is considered, whereKis a closed convex cone in IR3,Aλa real 3×3 matrix depending continuously on a real parameter λ,Ga small perturbation. Small periodic solutions bifurcating at λ0from the branch of trivial solutions are studied. It is proved that these solutions are stable or they are contained in a certain attracting set Aλif they correspond to parameters λ for which the trivial solution is unstable. Further, unstable solutions exist among them if they correspond to parameters for which the trivial solution is s

ISSN:0025-584X    

DOI:10.1002/mana.19991970106

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

摘要:

AbstractLetXbe a set of positive reach in thed‐dimensional Euclidean space. We present formulae for the integrals of the curvature measures of flat sections ofXwith respect to all translations/Euclidean motions of the sectioning flat. We consider the (generalized) curvature measures supported by the corresponding unit normal bundle. As a special case we obtain formulae for the spherical area measure

ISSN:0025-584X    

DOI:10.1002/mana.19991970107

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

摘要:

AbstractPrevious authors have considered generalizations of the David‐JournéT1 theorem to the scale of Triebel ‐ Lizorkin spaces (IRn) under theT1 = 0 andT= 0 assumptions, whereTis a (generalized) Calderon ‐ Zygmund operator. We prove boundedness on (IRn) under weaker assumptions onT1 andT1, which are related to the sharpT1,TBMOassumptions for in the David‐Journé theorem. In some cases we also show that our conditions are sharp. By similar techniques, we also obtain sharper conditions for “families of molecules” and “norming families”

ISSN:0025-584X    

DOI:10.1002/mana.19991970108

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

摘要:

AbstractWe consider the problem to reconstruct the mass distribution of a string where the mass is concentrated in a finite number of points, or, equivalently, the problem to reconstruct a simply connected mass spring system with unknown masses and stiffness parameters if the following data are given.Problem 1: The spectra of the string and of a modification of the string, or.Problem 2: The spectra of two different modifications of the string.Here a modification of the string is a string which appears if we link the unknown string with another string of known mass distribution.The paper contains a necessary condition for the existence of a solution of Problem 1, and explicit formulas and an algorithm for the solutions of the Problems 1 and 2 under the condition that there exists a solution.For the case that the mass distribution of the unknown string is not discrete we consider the problem to find discrete approximations of this distribution from the respective spectral data.The methods are based on the spectral theory of generalized second order differential operators as developed by M. G. Krein

ISSN:0025-584X    

DOI:10.1002/mana.19991970109

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

摘要:

AbstractWe study regular boundary value problems for ordinary differential equations with a variable complex ‐ valued coefficient at the principal term of the equation. Simple algebraic conditions on the coefficient that guarantee that a system of root functions of such boundary value problems forms an Abel basis have been foun

ISSN:0025-584X    

DOI:10.1002/mana.19991970110

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY

ISSN:0025-584X    

DOI:10.1002/mana.19991970101

出版商:WILEY‐VCH Verlag    

年代:1999

数据来源: WILEY