摘要:

The role of boundary conditions in assuring self-adjointness for the singular second order Sturm-Liouville operator -yn+ qy is discussed, both in the limit circle and limit point cases.

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631598

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Techniques from the theory of partial differential equations are used to prove the uniform convergence of the eigenfunction expansion associated with a two-parameter system of ordinary differential equations of the second order under left definiteness and semi-definitness assumptions.

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631599

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A very general class of quasi-differential expressions which generate J-symmetric operators in Hilbert space is defined with the aid of Green's formula and characterized in terms of the coefficients. Furthermore, the limit-point condition is discussed for not necessarily symmetric expressions.

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631600

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The aim of this note is to study the A-weakly compact operators using an arbitrary space ideal A. Since F ⊂ A the n-weakly compact operators of [9] are particular A-weakly compact operators.

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631601

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A connected, nontrivial, simple graph of order v is said to be α,β destructible if α,β are factors of v and an α-set of edges, E', exists whose removal from G isolates exactly the vertices in α,β-set V'. Graphs which are not α,β destructible for any α,β are called stable, If G is a stable graph on a prime number p ≥ 7 of vertices, then we show that G has a maximum number of edges if and only if G is K2,p-2, We also characterize stable graphs on a minimum number of edges.

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631602

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

We characterize and study the class of topological spaces that admit a coarsest quasi-proximity. This class of spaces generalizes the class of locally compact spaces in a natural way. It follows from our results that the two classes coincide in the class of super-sober spaces.

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631603

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

This paper contains an investigation of hereditary topological categories. Useful and illustrative descriptions and pleasant properties of their one-point-extensions are developed and used for a characterization of heredity. The results are applied to the problem to find necessary and sufficient conditions for a bi(co)reflective subcategory of a hereditary topological category to be hereditary. In the reflective case, preservation of certain subobjects by the reflector is sufficient; under the additional assumption of final density it is also necessary. Since a topological category is a topological universe (or quasitopos) iff it is Cartesian closed and hereditary. combination with results on Cartesian closedness yields results on topological universes similar to the ones on heredity.

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631604

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631605

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:1607-3606    

DOI:10.1080/16073606.1986.9631597

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor