摘要:

We prove the existence of invariant weak ideals for majorized compact operators with quasi-nilpotent exact majorant onbo-complete lattice normed spaces.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631806

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

SupposeMis a semifinite von Neumann algebra, τ a faithful semifinite normal trace onM, and [Mtilde] the space of τ-measurable operators. We examine the relationship between the norm-closed ideals inMand the measure-closed ideals in [Mtilde].

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631807

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Degeneration of an hyperbolic surface of finite volume (compact or non-compact) is precisely defined. Briefly, such a surface is continuously deformed so that the lengths of one or more simple, closed geodesics (called pinching geodesics) approach zero. In the limit, each pinching geodesic corresponds to two cusps on a well-defined limit surface. We prove here that the heat kernel on a degenerating surface converges to that of the limit surface. As a corollary, we obtain that the resolvent kernel also converges for a certain range of its spectral parameter.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631808

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

For an arbitrary infinite-dimensional Banach space 𝔛, we construct examples of strongly-measurable 𝔛-valued Pettis integrable functions whose indefinite Pettis integrals are nowhere weakly differentiable; thus, for these functions the Lebesgue Differentiation Theorem fails rather spectacularly. We also relate the degree of nondifferentia-bility of the indefinite Pettis integral to the cotype of 𝔛, from which it follows that our examples are reasonably sharp.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631809

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

We study the question of whether morphisms of a concrete category X can be determined by means of closure operators of X in the sense of [DT]. In particular, we show that closure operators cannot detect uniformly continuous maps in case X is the category of uniform spaces. We have analogous result for proximity spaces and topological modules.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631810

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In a unitary Banach algebra conditions are sought for an element, the spectrum of which is the singleton {1}, to be the identity of the algebra. Our main result is that this is true if the element is Abel bounded and doubly (N)-uniformly Abel bounded. This condition is fulfilled if the element is doubly power bounded in which case the theorem was proved by I. Gelfand [4] (1941). If the element is doubly Cesàro bounded, the result is due to M. Mbekhta and J. Zemánek [7, Theorem 2]. We present an example of a matrix which is Abel bounded and doubly (2)-Abel bounded, but not Cesàro bounded.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631811

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Since 1910 when H. Weyl first successfully attacked the singular Sturm-Liouville problem associated with

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631812

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper we consider a class of Hoehnke radicals of associative rings. A radicalHfrom this class is constructed using generalized semi-prime ideals determined by a ring regularity. It is shown that different regularitiesMaybe used to construct thesame radical H. Furthermore, we show that the K.A.-radical corresponding to one of the regularities which determines H is in fact complementary to H. As special cases we have that the radical defined by f-regularity is complementary to Bear's lower radical β, the radical defined byC-regularity is complementary to the generalized nil-radicalNgand that the quasi-radical and the λ-radical are complementary.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631813

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

Prime ringsMaybe classified by the sizes of the sets that‘insulate’ their elements from annihilation. For a cardinal m > 0, the class [Pbar]r,(m) of all rings that are right prime of ‘bound at most m’ is studied, with particular reference to its closure under constructions such as matrix rings, semigoup rings, orders and extensions. The classes [Pbar]r,(m) are special in the sense of radical theory for each m > 0. The attendant upper radicals υ[Pbar]r,(m) are right (and not left) strong; their compatibility with certain ring constructions is examined. In the lattice of radicals (where they form a strictly descending chain), their positions are described, relative to various familiar radicals.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631814

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor

摘要:

In this paper we conclude that the notion of a n-strongly (0-) minimal quasi-ideal and that of a regular, strongly (0-) minimal quasiideal coinside. Our related results, obtained independently from Clifford's results, present us with additional information on the last-named quasiideals. We give, as a by-product, a solution to a problem posed by L. Márki. Furthermore, we generalize two results of O. Steinfeld to the quasi-reflexive case, and on the other hand we sharpen the same results by means of n-strongly (0)-minimal quasi-ideals.

ISSN:1607-3606    

DOI:10.1080/16073606.1995.9631815

出版商:Taylor & Francis Group    

年代:1995

数据来源: Taylor