共查询到20条相似文献,搜索用时 0 毫秒
1.
A. Ülger 《Monatshefte für Mathematik》1996,121(4):353-379
LetA be a commutative Banach algebra with a nonempty spectrum A. By weak we denote the relative weak topology induced on A by (A
*,A
**). In this note we study some properties of the topological space (A, weak) and present some applications of the results obtained and tools used to amenability, weakly compact homomorphisms, weakly compact subsets of the spectrum of the uniform algebras and to a characterization of the synthesizable ideals of the algebraA. 相似文献
2.
Rasoul Nasr-Isfahani 《Quaestiones Mathematicae》2016,39(8):1005-1017
For a Lau algebra A, we study the Banach space WAP(A) of all weakly almost periodic functionals on A to obtain some equivalent conditions for the existence of topological left invariant means on a topological left introverted subspace X of A contained in WAP(A). Finally, we consider relations between the existence of a topological left invariant mean on X and a common fixed point property. 相似文献
3.
A.T.-M. Lau 《Journal of Functional Analysis》2005,225(2):263-300
It is shown how the basic constructs of harmonic analysis, such as convolution, algebras of measures and functions (including Fourier-Stieltjes algebras) can be developed for compact Hausdorff right topological groups. In particular, the properties and structure of these new objects are compared with their classical analogues in the topological group case. 相似文献
4.
Let
be a locally compact group. Consider the Banach algebra
, equipped with the first Arens multiplication, as well as the
algebra LUC
, the dual of the space of bounded left uniformly
continuous functions on
, whose product extends the convolution in
the measure algebra M
. We present (for the most interesting case
of a non-compact group) completely different - in particular,
direct - proofs and even obtain
sharpened versions of
the results, first proved by Lau-Losert in [9] and Lau in
[8], that the topological centres of the latter algebras
precisely are
and M
, respectively. The special interest of
our new approach lies in the fact that it shows a fairly general pattern
of solving the topological centre problem for various kinds of Banach
algebras; in particular, it avoids the use of any measure theoretical
techniques. At the same time, deriving both results in perfect
parallelity, our method reveals the nature of their close relation.Received: 1 January 2002 相似文献
5.
Danrun Huang 《Integral Equations and Operator Theory》1993,17(1):54-67
For a matrix over a complex commutative unital Banach algebra, necessary and sufficient conditions are given for the existence of its group inverse, and more generally, its Drazin inverses. The conditions are easy to check and explicit formulas for the inverses are provided. Some properties of the inverses and an application to operator theory are discussed. This note is a continuation of an earlier work of the author. 相似文献
6.
Gilles Pisier 《Integral Equations and Operator Theory》1998,31(3):353-370
There is a pair of commuting operators (T
1,T
2) on Hilbert space such that eachT
1 andT
2 is similar to a contraction but the pair (T
1,T
2) is not similar to a pair of contractions. There is a pair of commuting unitarizable representations (1,2) on the free group withN2 generators such that (1,2) is not similar to a pair of unitary representations. In connection with these examples, we introduce and study a notion of length for aC
*-algebra (or an operator algebra) generated by two subalgebras, which is analogous to the minimum length of a word in the generators of a group.Partially supported by the N.S.F. 相似文献
7.
Let φ be an Orlicz function that has a complementary function φ* and let ℓφ be an Orlicz sequence space. We prove two results in this paper. Result 1:
, the Fremlin projective tensor product of ℓφ with a Banach lattice X, has the Radon-Nikodym property if and only if both ℓφ and X have the Radon-Nikodym property. Result 2:
, the Wittstock injective tensor product of ℓφ with a Banach lattice X, has the Radon-Nikodym property if and only if both ℓφ and X have the Radon-Nikodym property and each positive continuous linear operator from hφ* to X is compact.
We dedicate this paper to the memory of H. H. Schaefer
The first-named author gratefully acknowledges support from the Faculty Research Program of the University of Mississippi
in summer 2004. 相似文献
8.
Danrun Huang 《Integral Equations and Operator Theory》1992,15(3):454-469
LetA be a matrix over a complex commutative unital Banach algebra. We give necessary and sufficient conditions forA to have a generalized inverse. Moreover, if the Banach algebra has a symmetric involution, these are also necessary and sufficient conditions forA to admit the Moore-Penrose inverse.Partially supported by NSF Grant DMS-8802593 相似文献
9.
For a space X denote by Cb(X) the Banach algebra of all continuous bounded scalar-valued functions on X and denote by C0(X) the set of all elements in Cb(X) which vanish at infinity. 相似文献
10.
Humberto E. Prado 《Acta Appl Math》1991,25(1):87-98
Local transformation groups acting on a manifold X define a natural action of on a space D(X), of functions on X. The natural action induces a local representation of on a Hilbert subspace of the space of distributions on D(X). 相似文献
11.
J. Vukman 《Aequationes Mathematicae》1988,36(2-3):165-175
Summary In the first section of this paper we consider some functional equations which are closely connected to derivations (i.e. additive mappings with the propertyD(ab) = aD(b) + D(a)b) on Banach algebras. IfD is a derivation on some algebraA, then the equationD(a) = – aD(a
–1
)a holds for all invertible elementsa A. It seems natural to ask whether this functional equation characterizes derivations among all additive mappings. It is too much to expect an affirmative answer to this question in arbitrary algebras, since it may happen that even in normed algebras the group of all invertible elements contains only scalar multiples of the identity. We try to answer the question above in Banach algebras, since in Banach algebras invertible elements exist in abundance. In the second section of the paper we prove some results concerning representability of quadratic forms by bilinear forms. 相似文献
12.
13.
14.
We construct different classes of lumpings for a family of Markov chain products which reflect the structure of a given finite poset. We essentially use combinatorial methods. We prove that, for such a product, every lumping can be obtained from the action of a suitable subgroup of the generalized wreath product of symmetric groups, acting on the underlying poset block structure, if and only if the poset defining the Markov process is totally ordered, and one takes the uniform Markov operator in each factor state space. Finally we show that, when the state space is a homogeneous space associated with a Gelfand pair, the spectral analysis of the corresponding lumped Markov chain is completely determined by the decomposition of the group action into irreducible submodules. 相似文献
15.
The main purpose of this paper is to study the continuity of several kinds of generalized inverses of elements in a Banach algebra with identity. We first obtain a sufficient and necessary condition for the lower semi-continuity of reflexive generalized inverses as set-valued mappings. Based on this result, we characterize the continuity of the Moore-Penrose inverse in a C∗-algebra and therefore, derive some new and well-known criteria in operator theory. 相似文献
16.
M. Hemdaoui 《Rendiconti del Circolo Matematico di Palermo》2004,53(3):369-380
The aim of this note is a discussion about a concept of convergence related to a spectral property in unital complex Banach
algebras. 相似文献
17.
18.
19.
In this note we classify the finite groups satisfying the following property P5: their conjugacy class lengths are set-wise relatively prime for any 5 distinct classes.Received: 6 October 2004; revised: 16 November 2004 相似文献
20.
Thierry Coulbois 《Archive for Mathematical Logic》2001,40(7):523-524
F. Oger proved that if A is a finite group, then the class of groups which are abelian-by-A can be axiomatized by a single first order sentence. It is established here that, in Oger's result, the word abelian cannot
be replaced by group.
Received: 15 March 1996 / Published online: 18 July 2001 相似文献