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1.
Let (X,τ1) and (Y,τ2) be two Hausdorff locally convex spaces with continuous duals X′ and Y′, respectively, L(X,Y) be the space of all continuous linear operators from X into Y, K(X,Y) be the space of all compact operators of L(X,Y). Let WOT and UOT be the weak operator topology and uniform operator topology on K(X,Y), respectively. In this paper, we characterize a full-invariant property of K(X,Y); that is, if the sequence space λ has the signed-weak gliding hump property, then each λ-multiplier WOT-convergent series ∑iTi in K(X,Y) must be λ-multiplier convergent with respect to all topologies between WOT and UOT if and only if each continuous linear operator T :(X,τ1)→(λβ,σ(λβ,λ)) is compact. It follows from this result that the converse of Kalton's Orlicz–Pettis theorem is also true. 相似文献
2.
A. K. Katsaras 《P-Adic Numbers, Ultrametric Analysis, and Applications》2009,1(3):190-203
LetX be a Hausdorff zero-dimensional topological space,K(X) the algebra of all clopen subsets of X, E a Hausdorff locally convex space over a non-Archimedean valued field and C
b
(X) the space of all bounded continuous -valued functions on X. The space M(K(X),E), of all bounded finitely-additive measures m: K(X) → E, is investigated. If we equip C
b
(X) with the topologies β
o
, β, β
u
, τ
b
or β
ob
, it is shown that, for E (compete, the corresponding spaces of continuous linear operators from C
b
(X) to E (are algebraically isomorphic to certain subspaces of M(K(X),E).
The text was submitted by the author in English. 相似文献
3.
Jussi Laitila 《Integral Equations and Operator Theory》2007,58(4):487-502
Analytic composition operators
are studied on X-valued versions of BMOA, the space of analytic functions on the unit disk that have bounded mean oscillation on the unit
circle, where X is a complex Banach space. It is shown that if X is reflexive and C
φ is compact on BMOA, then C
φ is weakly compact on the X-valued space BMOA
C
(X) defined in terms of Carleson measures. A related function-theoretic characterization is given of the compact composition
operators on BMOA. 相似文献
4.
Vlad Timofte 《Journal of Approximation Theory》2002,119(2):291-299
In this paper, we give special uniform approximations of functions u from the spaces CX(T) and C∞(T,X), with elements
of the tensor products CΓ(T)X, respectively C0(T,Γ)X, for a topological space T and a Γ-locally convex space X. We call an approximation special, if
satisfies additional constraints, namely supp vu−1(X\{0}) and
(T) co(u(T)) (resp. co(u(T){0})). In Section 3, we give three distinct applications, which are due exactly to these constraints: a density result with respect to the inductive limit topology, a Tietze–Dugundji's type extension new theorem and a proof of Schauder–Tihonov's fixed point theorem. 相似文献
5.
In this paper, which is a continuation of Timofte (J. Approx. Theory 119 (2002) 291–299, we give special uniform approximations of functions from CXY(T×S) and C∞(T×S,XY) by elements of the tensor products CX(T)CY(S), respectively C0(T,X)C0(S,Y), for topological spaces T,S and Γ-locally convex spaces X,Y (all four being Hausdorff). 相似文献
6.
Juan Carlos Ferrando 《Acta Mathematica Hungarica》2012,135(1-2):24-30
Let (Ω,Σ,μ) be a complete finite measure space and X a Banach space. If all X-valued Pettis integrals defined on (Ω,Σ,μ) have separable ranges we show that the space of all weakly μ-measurable (classes of scalarly equivalent) X-valued Pettis integrable functions with integrals of finite variation, equipped with the variation norm, contains a copy of?c 0 if and only if X does. 相似文献
7.
G. Schlüchtermann 《manuscripta mathematica》1991,73(1):397-409
A sufficient condition is given when a subspaceL⊂L
1(μ,X) of the space of Bochner integrable function, defined on a finite and positive measure space (S, Φ, μ) with values in a Banach spaceX, is locally uniformly convex renormable in terms of the integrable evaluations {∫
A
fdμ;f∈L}. This shows the lifting property thatL
1(μ,X) is renormable if and only ifX is, and indicates a large class of renormable subspaces even ifX does not admit and equivalent locally uniformly convex norm. 相似文献
8.
We study the Pettis integral for multi-functions defined on a complete probability space (Ω,Σ,μ) with values into the family cwk(X) of all convex weakly compact non-empty subsets of a separable Banach space X. From the notion of Pettis integrability for such an F studied in the literature one readily infers that if we embed cwk(X) into ?∞(BX∗) by means of the mapping defined by j(C)(x∗)=sup(x∗(C)), then j○F is integrable with respect to a norming subset of B?∞∗(BX∗). A natural question arises: When is j○F Pettis integrable? In this paper we answer this question by proving that the Pettis integrability of any cwk(X)-valued function F is equivalent to the Pettis integrability of j○F if and only if X has the Schur property that is shown to be equivalent to the fact that cwk(X) is separable when endowed with the Hausdorff distance. We complete the paper with some sufficient conditions (involving stability in Talagrand's sense) that ensure the Pettis integrability of j○F for a given Pettis integrable cwk(X)-valued function F. 相似文献
9.
Surjit Singh Khurana 《Czechoslovak Mathematical Journal》2001,51(2):433-437
Let X be a completely regular Hausdorff space, Cb(X) the space of all scalar-valued bounded continuous functions on X with strict topologies. We prove that these are locally convex topological algebras with jointly continuous multiplication. Also we find the necessary and sufficient conditions for these algebras to be locally m-convex. 相似文献
10.
Marian Nowak 《Topology and its Applications》2012,159(5):1421-1432
Let X be a completely regular Hausdorff space and Cb(X) be the space of all real-valued bounded continuous functions on X, endowed with the strict topology βσ. We study topological properties of continuous and weakly compact operators from Cb(X) to a locally convex Hausdorff space in terms of their representing vector measures. In particular, Alexandrov representation type theorems are derived. Moreover, a Yosida-Hewitt type decomposition for weakly compact operators on Cb(X) is given. 相似文献
11.
Let T be a locally compact Hausdorff space and let C
0(T) be the Banach space of all complex valued continuous functions vanishing at infinity in T, provided with the supremum norm. Let X be a quasicomplete locally convex Hausdorff space. A simple proof of the theorem on regular Borel extension of X-valued -additive Baire measures on T is given, which is more natural and direct than the existing ones. Using this result the integral representation and weak compactness of a continuous linear map u: C
0(T) X when c
0 X are obtained. The proof of the latter result is independent of the use of powerful results such as Theorem 6 of [6] or Theorem 3 (vii) of [13]. 相似文献
12.
J. M. A. M. van Neerven 《Semigroup Forum》1991,43(1):378-394
The adjoint of aC
0-semigroup on a Banach spaceX induces a locally convex σ(X,X
ℴ)-topology inX, which is weaker than the weak topology ofX. In this paper we study the relation between these two topologies. Among other things a class of subsets ofX is given on which they coincide. As an application, an Eberlein-Shmulyan type theorem is proved for the σ(X,X
ℴ)-topology and it is shown that the uniform limit of σ(X,X
ℴ)-compact operators is σ(X,X
ℴ)-compact. Finally our results are applied to the problem when the Favard class of a semigroup equals the domain of the infinitesimal
generator. 相似文献
13.
Dhruba R. Adhikari 《Nonlinear Analysis: Theory, Methods & Applications》2011,74(14):4622-4641
Let X be an infinite dimensional real reflexive Banach space with dual space X∗ and G⊂X, open and bounded. Assume that X and X∗ are locally uniformly convex. Let T:X⊃D(T)→2X∗ be maximal monotone and strongly quasibounded, S:X⊃D(S)→X∗ maximal monotone, and C:X⊃D(C)→X∗ strongly quasibounded w.r.t. S and such that it satisfies a generalized (S+)-condition w.r.t. S. Assume that D(S)=L⊂D(T)∩D(C), where L is a dense subspace of X, and 0∈T(0),S(0)=0. A new topological degree theory is introduced for the sum T+S+C, with degree mapping d(T+S+C,G,0). The reason for this development is the creation of a useful tool for the study of a class of time-dependent problems involving three operators. This degree theory is based on a degree theory that was recently developed by Kartsatos and Skrypnik just for the single-valued sum S+C, as above. 相似文献
14.
Yu. È. Linke 《Siberian Mathematical Journal》2011,52(3):501-511
Given a continuous sublinear operator P: V → C(X) from a Hausdorff separable locally convex space V to the Banach space C(X) of continuous functions on a compact set X we prove that the subdifferential ∂P at zero is operator-affinely homeomorphic to the compact subdifferential ∂
c
Q, i.e., the subdifferential consisting only of compact linear operators, of some compact sublinear operator Q: ł2 → C(X) from a separable Hilbert space ł2, where the spaces of operators are endowed with the pointwise convergence topology. From the topological viewpoint, this
means that the space L
c
(ł2, C(X)) of compact linear operators with the pointwise convergence topology is universal with respect to the embedding of the subdifferentials
of sublinear operators of the class under consideration. 相似文献
15.
H. Y. Zhou 《Applied Mathematics Letters》2001,14(8):13
Let X be an arbitrary Banach space, K be a nonempty closed convex subset of X, and T : K → K be a Lipschitzian and hemicontractive mapping with the property lim inft→∞((t)/t) > 0. It is shown that the Ishikawa iteration procedures are weakly T-stable. As consequences, several related results deal with the weak stability of these procedures for the iteration proximation of solutions of nonlinear equations involving accretive operators. Our results improve and extend those corresponding results announced by Osilike. 相似文献
16.
Dumitru Popa 《Proceedings Mathematical Sciences》2009,119(2):221-230
Let Ω be a compact Hausdorff space, X a Banach space, C(Ω, X) the Banach space of continuous X-valued functions on Ω under the uniform norm, U: C(Ω, X) → Y a bounded linear operator and U
#, U
# two natural operators associated to U. For each 1 ≤ s < ∞, let the conditions (α) U ∈ Π
s
(C(Ω, X), Y); (β)U
# ∈ Π
s
(C(Ω), Π
s
(X, Y)); (γ) U
# ε Π
s
(X, Π
s
(C(Ω), Y)). A general result, [10, 13], asserts that (α) implies (β) and (γ). In this paper, in case s = 2, we give necessary and sufficient conditions that natural operators on C([0, 1], l
p
) with values in l
1 satisfies (α), (β) and (γ), which show that the above implication is the best possible result. 相似文献
17.
In this paper, we show that the strong conical hull intersection property (CHIP) completely characterizes the best approximation to any x in a Hilbert space X from the set
K:=C∩{xX:-g(x)S},