共查询到20条相似文献,搜索用时 31 毫秒
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Petr Hájek 《Israel Journal of Mathematics》1998,107(1):237-252
We show that every Fréchet differentiable real function onC(K), K scattered with locally uniformly continuous derivative has locally compact derivative. Using this and similar results, we
investigate the existence ofC
2-Fréchet smooth surjections between various Banach spaces. 相似文献
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Some conditions of barrelledness are considered and studied on the spaceC 0(E), defined as follows: IfE is a real or complex Hausdorff locally convex space and \(P_E \) is a saturated family of seminorms, defining the original topology ofE, then the vector space of all the sequences \(\bar f = \left\{ {\bar f(n): n \in \mathbb{N}} \right\}\) inE, convergent to zero, provided with the locally convex topology $$\bar p(\bar f) = sup\left\{ {p (\bar f(n)): n \in \mathbb{N}} \right\}p \in P_E $$ is defined as the spaceC 0(E). The main result of the paper is the following characterization:C 0(E) is quasibarrelled (see [3], p. 367) if and only if,E is quasibarrelled and the strong dual ofE has property (B) (see [5], p. 30, for definition). We obtain. as a consequence, commutativity properties of the operatorC 0, acting on certain inductive limits (3.3 Theorem). We also prove thatC 0 does not commute with uncountably strict inductive limits. In particular, there are ultrabornological spacesE for whichC 0(E) is not quasibarrelled. 3.1. Example provides a complete?-tensor product of two complete ultrabornological spaces which is not quasibarrelled. 相似文献
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Cho-Ho Chu 《Mathematische Zeitschrift》1988,199(1):129-131
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Hans Jarchow 《Mathematische Annalen》1986,273(2):341-343
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Ulrich Groh 《Israel Journal of Mathematics》1984,47(2-3):227-235
LetT be an identity preserving Schwarz map on aC
*-algebra. The following conditions are proved to be equivalent: (a)T is uniformly ergodic with finite-dimensional fixed space. (b)T is quasi-compact. 相似文献
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3×3上三角算子矩阵的Weyl型定理 总被引:1,自引:0,他引:1
设A∈B(H1),B∈B(H2),C∈B(H3)为给定的三个算子,用M(D,E,F)= 表示一个作用在H1(?)H2(?)H3上的3×3算子矩阵.本文首先给出存在算子D∈B(H2,H1),E∈B(H3,H1),F∈B(H3,H2),使得M(D,E,F)为上半Fredholm算子(下半Fredholm算子)的充要条件.同时研究了3×3算子矩阵 M(D,E,F)的Weyl定理,α-Weyl定理,Browder定理和α-Browder定理. 相似文献
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Jari Taskinen 《Israel Journal of Mathematics》1995,92(1-3):207-219
We prove a universal mapping theorem for “integral” holomorphic mappings on the open unit ball ofC(K). In our theorem, the universal space isC(K), and the universal mapping is increasing in the positive cone ofC(K). 相似文献
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Fang Liping 《数学学报(英文版)》1993,9(2):160-165
It is a general problem to study the measure of Julia sets. There are a lot of results for rational and entire functions.
In this note, we describe the measure of Julia set for some holomorphic self-maps onC
*. We'll prove thatJ(f) has positive area, wheref:C
*→C
*,f(z)=z
m
c
P(z)+Q(1/z)
,P(z) andQ(z) are monic polynomials of degreed, andm is an integer. 相似文献
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Allan Pinkus 《Constructive Approximation》1988,4(1):85-96
C 1(K) is the space of real continuous functions onK endowed with the usualL 1,-norm where \(K = \overline {\operatorname{int} K}\) is compact inR m · U is a finite-dimensional subspace ofC 1,(K). The metric projection ofC 1,(K) ontoU contains a continuous selection with respect toL 1, -convergence if and only ifU is a unicity (Chebyshev) space forC 1,(K). Furthermore, ifK is connected andU is not a unicity space forC 1,(K), then there is no continuous selection with respect toL ∞-convergence. An example is given of aU and a disconnectedK with no continuous selection with respect toL 1-convergence, but many continuous selections with respect toL ∞-convergence. 相似文献
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L. P. Vlasov 《Mathematical Notes》1997,61(1):38-47
Functionals (vector measures) defined on the spaceC(Q, X) of continuous abstract functions (whereQ is a compact Hausdorff space andX is a Banach space) and attaining their norm on the unit sphere are considered. A characterization of such functionals is
given in terms of the Radon-Nikodym derivative of the vector measure with respect to the variation of the measure and in terms
of analogs of the derivative. Applications to the characterization of finite-codimensional subspaces with the best approximation
property are given. Similar results are obtained for the spaceB(Q, Σ, X) of uniform limits of simple functions.
Translated fromMatematicheskie Zametki, Vol. 61, No. 1, pp. 45–56, January, 1997.
Translated by V. E. Nazaikinskii 相似文献
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Dan Timotin 《Integral Equations and Operator Theory》1986,9(2):295-304
For a certain class of operators defined by integral kernels, a necessary and sufficient condition is given for the belonging to the Schatten-von Neumann idealsC
P. The operators considered generalize the classical Hankel operators; the results thus extend Peller's characterization of the Hankel operators in a classC
P. 相似文献
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