共查询到20条相似文献,搜索用时 15 毫秒
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Michael Pannenberg 《Rendiconti del Circolo Matematico di Palermo》1991,40(2):215-240
We show that the tensor product of commutative Banach algebras possesses a finite universal Korovkin system, if and only if each of the factors does, and present an explicit construction of finite universal Korovkin systems for several commutative Banach algebras of vector-valued functions. The same questions are answered for the formation of direct sums and the passage to an ideal resp. its associated quotient algebra. 相似文献
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A. El Kinani 《Rendiconti del Circolo Matematico di Palermo》2007,56(3):369-380
We consider the space, where Ω is a family of weights. We give a sufficient condition, on Ω, for to be locally convex algebra with continuous multiplication. Examples of such weights are also provided. 相似文献
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Sen-Zhong Huang Jan van Neerven Frank Rä biger 《Proceedings of the American Mathematical Society》1998,126(5):1397-1407
Let be a locally compact abelian group. A function is said to be a weight if it is locally bounded, Borel measurable and submultiplicative. We call a weight on semi-bounded if there exist a constant and a subsemigroup with such that
for all Using functional analytic methods, we show that all Beurling algebras whose defining weight is semi-bounded satisfy Ditkin's condition.
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We describe Novikov-Poisson algebras in which a Novikov algebra is not simple while its corresponding associative commutative
derivation algebra is differentially simple. In particular, it is proved that a Novikov algebra is simple over a field of
characteristic not 2 iff its associative commutative derivation algebra is differentially simple. The relationship is established
between Novikov-Poisson algebras and Jordan superalgebras.
Supported by RFBR (grant No. 05-01-00230), by SB RAS (Integration project No. 1.9), and by the Council for Grants (under RF
President) and State Aid of Leading Scientific Schools (project NSh-344.2008.1).
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Translated from Algebra i Logika, Vol. 47, No. 2, pp. 186–202, March–April, 2008. 相似文献
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Stefano Serra Capizzano. 《Mathematics of Computation》2000,69(232):1533-1558
We consider sequences of matrices with a block structure spectrally distributed as an -variate matrix-valued function , and, for any , we suppose that is a linear and positive operator. For every fixed we approximate the matrix in a suitable linear space of matrices by minimizing the Frobenius norm of when ranges over . The minimizer is denoted by . We show that only a simple Korovkin test over a finite number of polynomial test functions has to be performed in order to prove the following general facts:
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- the sequence is distributed as ,
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- the sequence is distributed as the constant function (i.e. is spectrally clustered at zero).
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Given a weighted discrete abelian semigroup (S, ω), the semigroup M
ω
(S) of ω-bounded multipliers as well as the Rees quotient M
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(S)/S together with their respective weights [(w)\tilde]\tilde{\omega} and [(w)\tilde]q\tilde{\omega}_q induced by ω are studied; for a large class of weights ω, the quotient l1(Mw(S),[(w)\tilde])/l1(S,w)\ell^1(M_{\omega}(S),\tilde{\omega})/\ell^1(S,{\omega}) is realized as a Beurling algebra on the quotient semigroup M
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(S)/S; the Gel’fand spaces of these algebras are determined; and Banach algebra properties like semisimplicity, uniqueness of uniform
norm and regularity of associated Beurling algebras on these semigroups are investigated. The involutive analogues of these
are also considered. The results are exhibited in the context of several examples. 相似文献
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Ebrahim Samei 《Journal of Mathematical Analysis and Applications》2008,346(2):451-467
Let be a Beurling algebra on a locally compact abelian group G. We look for general conditions on the weight which allows the vanishing of continuous derivations of . This leads us to introducing vector-valued Beurling algebras and considering the translation of operators on them. This is then used to connect the augmentation ideal to the behavior of the derivation space. We apply these results to give examples of various classes of Beurling algebras which are weakly amenable, 2-weakly amenable or fail to be even 2-weakly amenable. 相似文献
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If an algebraA is quantum commutative with respect to the action of a quasitriangular Hopf algebraH, then the monoidal structure on the categoryH
ℳ
of modules overH induces a rnonoidal structure on the categoryA#H
ℳ
of modules over the associated smash productA # H. The condition under which the braiding structure ofH
ℳ
induces a braiding structure onA#H
ℳ
is further investigated. Dually, the notion of quantum cocommutativity is introduced, and similar result in this dual situation
is obtained. 相似文献
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Prof. Richard D. Mosak 《Monatshefte für Mathematik》1978,85(2):115-124
In this note some questions of ideal theory for the center and more generally theB-fixed subalgebras of a Beurling algebraL
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(G) are discussed. Sufficient conditions on are given for these subagebras to satisfy Ditkin's condition, or for primary ideals to be maximal or at least of finite codimension.Research partially supported by the National Science Foundation. 相似文献
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