摘要:

AbstractPseudodifferential operators with symbols on a Hilbert phase space are defined as symmetric operators inL2given by a smooth measure. The main formulae of symbolic calculus are proved in this context.

ISSN:0025-584X    

DOI:10.1002/mana.19981920102

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractA standard system of interval linear equations is defined byAx= b, where A is anm×ncoefficient matrix with (compact) intervals as entries, andbis anm‐dimensional vector whose components are compact intervals. It is known that for systems of interval linear equations the solution set, i. e., the set of all vectorsxfor whichAx=bfor someAϵAandbϵb, is a polyhedron.In some cases, it makes sense to consider not all possibleAϵAandbϵb, but only thoseAandbthat satisfy certain linear conditions describing dependencies between the coefficients. For example, if we allow only symmetric matricesA(aij= aji), then the corresponding solution set becomes (in general) piecewise‐quadratic.In this paper, we show that for general dependencies, we can have arbitrary (semi)algebraic sets as projections of solut

ISSN:0025-584X    

DOI:10.1002/mana.19981920103

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractThe solution of a stationary boundary value problem on a domain with conical points has singularities near these points. Here we first consider existence results in appropriate weighted Sobolev spaces in order to incorporate the singularities. We secondly use these results to prove existence, uniqueness and regularity of solutions of non‐autonomous second order evolution equations on such domain

ISSN:0025-584X    

DOI:10.1002/mana.19981920104

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractIn this paper, we consider some conditions of finiteness related to thep‐class field tower problem over an imaginary quadratic field, wherepis an odd prim

ISSN:0025-584X    

DOI:10.1002/mana.19981920105

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractIn this paper we present a different method for proving symmetry results in partial differential equations. The principal idea is to use the classical tool of shape optimization, namely, the differentiation with respect to the domain. The aim is to derive, from an optimality condition, information on the boundary of the domain.

ISSN:0025-584X    

DOI:10.1002/mana.19981920106

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractWe study some aspects of the relationship between the long time behaviour of systems with a finite but large number of components and their idealizations with countably many components. The following class of models is considered in detail, which contains examples occuring in population growth and population genetic models.

ISSN:0025-584X    

DOI:10.1002/mana.19981920107

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractIn the study of the resolvent of a scalar elliptic operator, say, on a manifold without boundary there is a well‐known Agmon‐Agranovich‐Vishik condition of ellipticity with parameter which guarantees the existence of a ray of minimal growth of the resolvent. The paper is devoted to the investigation of the same problem in the case of systems which are elliptic in the sense of Douglis‐Nirenberg. We look for algebraic conditions on the symbol providing the existence of the resolvent set containing a ray on the complex plane. We approach the problem using the Newton polyhedron method. The idea of the method is to study simultaneously all the quasihomogeneous parts of the system obtained by assigning to the spectral parameter various weights, defined by the corresponding Newton polygon. On this way several equivalent necessary and sufficient conditions on the symbol of the system guaranteeing the existence and sharp estimates for the resolvent are found. One of the equivalent conditions can be formulated in the following form: all the upper left minors of the symbol satisfy ellipticity conditions. This subclass of systems elliptic in the sense of Douglis‐Nirenberg was introduced by A. KOZHEVN

ISSN:0025-584X    

DOI:10.1002/mana.19981920108

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractIn the first part we give necessary and sufficient conditions for the existence of a stable almost complex structure on a 10‐manifoldMwithH1(M;ℤ)= 0 and no 2‐torsion inH1(M;ℤ)fori= 2,3. Using the Classification Theorem of Donaldson we give a reformulation of the conditions for a 4‐manifold to be almost complex in terms of Betti numbers and the dimension of the ±‐eigenspaces of the intersection form. In the second part we give general conditions for an almost complex manifold to admit infinitely many almost complex structures and apply these to symplectic manifolds, to homogeneous spaces and to complete i

ISSN:0025-584X    

DOI:10.1002/mana.19981920109

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractIn affine differential geometry, three natural connections can be considered, namely the induced connection, the Levi Civita connection of the affine metric and the conjugate connection. Quadrics are characterized by the conditions that all the pre‐geodesies with respect to one of these connections are also pre‐geodesies with respect to the other two connections. In the present paper we describe 3‐dimensional affine hypersurfaces for which some of the geodesies or pre‐geodesies for the different connections c

ISSN:0025-584X    

DOI:10.1002/mana.19981920110

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY

摘要:

AbstractWe shall explicitly evaluate important constants in embedding theorems and Hölder‐regularity theorems for an elliptic equation of the ty

ISSN:0025-584X    

DOI:10.1002/mana.19981920111

出版商:WILEY‐VCH Verlag    

年代:1998

数据来源: WILEY