共查询到20条相似文献,搜索用时 46 毫秒
1.
Niels Jakob Laustsen 《K-Theory》2001,22(3):241-249
Let
Figiel's reflexive Banach space which is not isomorphic to its Cartesian square. We show that the K
0group of the algebra
of continuous, linear operators on
contain a subgroup isomorphic to the group c
00(
) of sequences
rational numbers with z
n=0 eventually. 相似文献
2.
Huang Jianfeng Wang Yuanheng 《高校应用数学学报(英文版)》2007,22(3):311-315
This paper studies the convergence of the sequence defined by x0∈C,xn 1=αnu (1-αn)Txn,n=0,1,2,…, where 0 ≤αn ≤ 1, limn→∞αn = 0, ∑∞n=0 αn = ∞, and T is a nonexpansive mapping from a nonempty closed convex subset C of a Banach space X into itself. The iterative sequence {xn} converges strongly to a fixed point of T in the case when X is a uniformly convex Banach space with a uniformly Gateaux differentiable norm or a uniformly smooth Banach space only. The results presented in this paper extend and improve some recent results. 相似文献
3.
B. S. Zakirov 《Siberian Advances in Mathematics》2009,19(2):128-149
We consider the Orlicz-Kantorovich modules L M (?,m) associated with a complete Boolean algebra ?, an N-function M, and a measure m defined on ? and taking values in the algebra L 0 of all measurable real functions. We obtain an analytic representation of the continuous L 0-valued homomorphisms defined on such modules. 相似文献
4.
《Indagationes Mathematicae》2019,30(5):930-942
We extend the notions of -convexity and -concavity for Banach ideals of measurable functions following an asymptotic procedure. We prove a representation theorem for the spaces satisfying both properties as the one that works for the classical case: each almost -convex and almost -concave space is order isomorphic to an almost--space. The class of almost--spaces contains, in particular, direct sums of (infinitely many) -spaces with different norms, that are not in general -convex – nor -concave –. We also analyze in this context the extension of the Maurey–Rosenthal factorization theorem that works for -concave operators acting in -convex spaces. In this way we provide factorization results that allow to deal with more general factorization spaces than -spaces. 相似文献
5.
Valentin Ferenczi 《Journal of Functional Analysis》2009,257(1):149-1060
We prove three new dichotomies for Banach spaces à la W.T. Gowers' dichotomies. The three dichotomies characterise respectively the spaces having no minimal subspaces, having no subsequentially minimal basic sequences, and having no subspaces crudely finitely representable in all of their subspaces. We subsequently use these results to make progress on Gowers' program of classifying Banach spaces by finding characteristic spaces present in every space. Also, the results are used to embed any partial order of size ℵ1 into the subspaces of any space without a minimal subspace ordered by isomorphic embeddability. 相似文献
6.
7.
Spiros A. Argyros 《Proceedings of the American Mathematical Society》2001,129(11):3231-3239
It is shown that every separable Banach space universal for the class of reflexive Hereditarily Indecomposable space contains isomorphically and hence it is universal for all separable spaces. This result shows the large variety of reflexive H.I. spaces.
8.
For any finite commutative idempotent semigroup S, a semilattice, we show how to compute the amenability constant of its semigroup algebra ℓ
1(S). This amenability constant is always of the form 4n+1. We then show that these give lower bounds to amenability constants of certain Banach algebras graded over semilattices.
We also give example of a commutative Clifford semigroups G
n
whose semigroup algebras ℓ
1(G
n
) admit amenability constants of the form 41+4(n−1)/n. We also show there is no commutative semigroup whose semigroup algebra has an amenability constant between 5 and 9.
N. Spronk’s research was supported by NSERC Grant 312515-05. 相似文献
9.
Niels Jakob Laustsen 《K-Theory》2001,23(2):115-127
We prove that the K-groups of the Banach algebra
of bounded, linear operators on the pth James space
, where 1 < p < , are given by
and
. Moreover, for each Banach space
and each non-zero, closed ideal
contained in the ideal of inessential operators, we show that
and
. This enables us to calculate the K-groups of
for each Banach space
which is a direct sum of finitely many James spaces and
-spaces. 相似文献
10.
Stuart F. Cullender 《Journal of Mathematical Analysis and Applications》2007,326(2):1291-1309
For a Banach space Y, the question of whether Lp(μ,Y) has an unconditional basis if 1<p<∞ and Y has unconditional basis, stood unsolved for a long time and was answered in the negative by Aldous. In this work we prove a weaker, positive result related to this question. We show that if (yj) is a basis of Y and (di) is a martingale difference sequence spanning Lp(μ) then the sequence (di⊗yj) is a basis of Lp(μ,Y) for 1?p<∞. Moreover, if 1<p<∞ and (yj) is unconditional then (di⊗yj) is strictly dominated by an unconditional tensor product basis. In addition, for 1<p<∞, we show that if (di)⊂Lp(μ) is a martingale difference sequence then there exists a constant K>0 so that
11.
Let (X,T) be a topological dynamical system. A pair of points (x,y)∈X2 is called Banach proximal if for any ε>0, the set {n∈Z+:d(Tnx,Tny)<ε} has Banach density one. We study the structure of the Banach proximal relation. A useful tool is the notion of the support of a topological dynamical system. We show that a dynamical system is strongly proximal if and only if every pair in X2 is Banach proximal. A subset S of X is Banach scrambled if every two distinct points in S form a Banach proximal pair but not asymptotic. We construct a dynamical system with the whole space being a Banach scrambled set. Even though the Banach proximal relation of the full shift is of first category, it has a dense Mycielski invariant Banach scrambled set. We also show that for an interval map it is Li–Yorke chaotic if and only if it has a Cantor Banach scrambled set. 相似文献
12.
We construct an example of a nonseparable Banach space which does not admit a support set.2 It is a consistent (and necessarily independent from the axioms of ZFC) example of a space C(K) of continuous functions on a compact Hausdorff K with the supremum norm. The construction depends on a construction of a Boolean algebra with some combinatorial properties. The space is also hereditarily Lindelöf in the weak topology but it doesn't have any nonseparable subspace nor any nonseparable quotient which is a C(K) space for K dispersed. 相似文献
13.
Let X be a real locally uniformly convex Banach space with normalized duality mapping J:X→2X*. The purpose of this note is to show that for every R>0 and every x0X there exists a function , which is nondecreasing and such that (r)>0 for r>0,(0)=0 and for all . Simply, it is shown that the necessity part of the proof of the original analogous necessary and sufficient condition of Prüß, for real uniformly convex Banach spaces, goes over equally well in the present setting. This is a natural setting for the study of many existence problems in accretive and monotone operator theories. 相似文献
14.
15.
《Journal of Functional Analysis》2023,284(10):109888
The construction of the free Banach lattice generated by a real Banach space is extended to the complex setting. It is shown that for every complex Banach space E there is a complex Banach lattice containing a linear isometric copy of E and satisfying the following universal property: for every complex Banach lattice , every operator admits a unique lattice homomorphic extension with . The free complex Banach lattice is shown to have analogous properties to those of its real counterpart. However, examples of non-isomorphic complex Banach spaces E and F can be given so that and are lattice isometric. The spectral theory of induced lattice homomorphisms on is also explored. 相似文献
16.
In this note we give generalizations of Noguchi's convergence-extension theorem to the case of infinite dimension.
17.
We study relations between Schatten classes and product operator ideals, where one of the factors is the Banach ideal ΠE,2 of (E, 2)‐summing operators, and where E is a Banach sequence space with ?2 ? E. We show that for a large class of 2‐convex symmetric Banach sequence spaces the product ideal ΠE,2 ○ ??aq,s is an extension of the Schatten class ??F with a suitable Lorentz space F. As an application, we obtain that if 2 ≤ p, q < ∞, 1/r = 1/p + 1/q and E is a 2‐convex symmetric space with fundamental function λE(n) ≈? n1/p, then ΠE,2 ○ Πq is an extension of the Schatten class ??r,q (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
18.
T. S. S. R. K. Rao 《Proceedings Mathematical Sciences》1997,107(1):35-42
In this paper we study a geometric property for Banach spaces called condition (*), introduced by de Reynaet al in [3], A Banach space has this property if for any weakly null sequencex
n of unit vectors inX, ifx
*
n
is any sequence of unit vectors inX
* that attain their norm at xn’s, then
. We show that a Banach space satisfies condition (*) for all equivalent norms iff the space has the Schur property. We also
study two related geometric conditions, one of which is useful in calculating the essential norm of an operator. 相似文献
19.
20.
Guohui Tian 《K-Theory》2000,19(2):185-193
Let A be a complex Banach algebra. In this paper, we prove a periodicity theorem that K(S
2
A, G, )K(A, G,), where (A,G,) is a finite covariant system and K(A,G,) is an Abelian group associated with (A,G,). 相似文献