摘要:

A familyKof rightR-modules is called a natural class ifKis closed under submodules, direct sums, infective hulls, and isomorphic copies. The main result of this note is the following: LetKbe a natural class on Mod-RandMεK. IfMsatisfies a.c.c. (or d.c.c.) on the set of submodules {N⊆M:M/Nε K}, then each nil subring of End(MR) is nilpotent.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631821

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Due to the existence of constants, classical topological categories cannot be universal in the sense of containing each concrete category as a full subcategory. In the point-free case, this obstruction vanishes and the question of universality makes sense again. The main problem, namely that as to whether the category of locales and localic morphisms is universal is still open; we prove, however, the universality of the following categories:

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631822

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this note we prove that if a linear bounded operatorTfroml1to a Banach spaceYis not an isomorphism, then there exists an elementf= (f1,f2,…) εl∞such that |fn| = 1 for everynand dist (f, T*Y*) = 1. This result we apply to Sidon sets in the theory of Fourier series.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631823

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Let M be a complete MV-algebra with square roots. Then every M-valued filter can be represented as “intersection” of an appropriate family ofmaximalM-valued filters. In the case of M = [0,1] maximal [0,1]-valued filters andfinitely additiveprobability measures come to the same thing.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631824

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Some strong and one-sided hereditary radicals connected with the Brown-McCoy radical are studied.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631825

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This paper is devoted to the study of groups with the property that the Frattini factor group is aT-group, i.e. a group in which every subnormal subgroup is normal. We give necessary and suffucient conditions for a direct productG = H x Kof finite groupsHandKto have such a property. Some structure theorems are also discussed.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631826

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Abstract extrapolation spaces for strongly continuous semigroups of linear operators on Banach spaces have been constructed by various methods (see, e.g., [Am (1988)], [DaP-Gr (1984)], [Na (1983)], [Ne (1992)], [Wa (1986)]). Usually they appear as “artefacts” used in some intermediate step in order to solve the Cauchy problem on the original space. Only in a few cases (see the papers by the Dutch school onX⊙*, e.g., [Ne (1992)]), and in sharp contrast to the situation for interpolation spaces (see, e.g., [Gr (1969)], [DiB (1991)], [Lu (1985)], [Ac-Te (1987)]), the extrapolation spaces have been identified in a concrete way. It is our intention to fill this gap and subsequently to give an application of the extrapolation method to a perturbation problem.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631827

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The notion of Cauchy point (= regular Cauchy filter) and the corresponding Cauchy spectrum, for a nearness frame (= uniform without the star-refinement condition) are investigated in various directions, including basic motivation, several functorial aspects, and the recognition of the Cauchy spectrum as the ordinary spectrum of the completion, after the unique existence of the latter is obtained as a central new result in this context.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631828

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The author and Mishra [1] have introduced some curvature tensors to study their relativistic and geometric properties. Matsumoto and Mihai [2] have introduced the notion of Lorentzian para Sasakian (LP-Sasakian) and studied certain transformations. In this paper some properties of curvature tensors, in a LP-Sasakian manifold, are studied.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631829

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In this paper we obtain classification and extension theorems for uniform spaces, using the Čech cohomology theory based on the finite uniform coverings, and study the associated cohomological dimension theory. In particular, we extend results for the cohomological dimension theory on compact Hausdorff spaces or compact metric spaces to those for our cohomological dimension theory on uniform spaces.

ISSN:1607-3606    

DOI:10.1080/16073606.1996.9631830

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor