摘要:

Rings which allow only the trivial hereditary torsion theories on their category of modules are characterised.

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631554

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Operators T which are both majorizing and cone absolutely summing on a Banach lattice E are investigated. Compactness and nuclearity of such operators are discussed and it is shown that a trace can be defined for operators belonging to a large class of these operators. Special results are derived in the case where E is a Banach function space and T a kernel operator. Finally we derive strongly measurable representations for a certain class of cone absolutely summing operators thereby clarifying work done by Dinculeanu and J.J. Uhl.

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631555

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

Theorem. Let X have a Hausdorff compactification YX with | Cℓγ X(γ X—x)| ⋚ x0. The following are equivalent:

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631556

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

For an arbitrary left R-module M, we denote by F(M) the class of left R-modules F such that for any exact sequence 0 → A α→ B of left R-modules and any R-homomorphism β: A → M factoring through F, there exists an R- homomorphism γ: B → M such that β = γα. For any given class R of left R-modules, we denote∩EϵRF(M) by F(R) or simply by 9 if the context is clear. The class of short exact sequences E of left R-modules relative to which each ME'JR has the injective property, is denoted by E(R) or just &. Relative properties of RR, F and E are investigated for a given class R. The special case where JR is the class of all pure-injective left R-modules is explored. In this way the class F of coflat left R-modules is introduced and it is pointed out that a module is coflat if and only if it is absolutely pure.

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631557

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

It is shown that, for some types of locally compact abelian groups G, the ideals in L1(G) having spectral synthesis may be characterized as the kernels of convolution operators induced by almost periodic functions.

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631558

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631559

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

摘要:

To form products of differential expressions in the classical way it is necessary to place heavy differentiability assumptions on the coefficients. Here we consider symmetric (formally self-adjoint) expressions defined, not in the classical way, but in terms of quasi-derivatives. With this very general notion of symmetry we show that products such as M1M2MI of symmetric expressions M1, Hp can be formed vithout any smoothness assumptions on the coefficients and such products are symmetric expressions.

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631560

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631561

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor

ISSN:1607-3606    

DOI:10.1080/16073606.1978.9631553

出版商:Taylor & Francis Group    

年代:1978

数据来源: Taylor