共查询到20条相似文献,搜索用时 15 毫秒
1.
Keiji Izuchi Shû ichi Ohno 《Proceedings of the American Mathematical Society》2006,134(5):1359-1364
We study Hankel-type operators on the space of bounded harmonic functions on the open unit disk. These operators are related to tight uniform algebras, the Dunford-Pettis property, and Bourgain algebras.
2.
We deal with the space consisting of those analytic functions on the unit disc such that , with . We determine the critical rate of decay of such that the pointwise multiplication operator , and analytic, has closed range in only in the trivial case that is the product of an invertible function in and a finite Blaschke product.
3.
In this paper, we study the matrix multiplication operators on Banach function spaces and discuss their applications in semigroups
for solving the abstract Cauchy problem. 相似文献
4.
Zhongqiu Ye 《Proceedings of the American Mathematical Society》2005,133(11):3355-3360
The relative growth of successive coefficients of odd univalent functions is investigated. We prove that a conjecture of Hayman is true.
5.
Eigenvalues and stability properties of multiplication operators and multiplication semigroups 下载免费PDF全文
Retha Heymann 《Mathematische Nachrichten》2014,287(5-6):574-584
We investigate uniform, strong, weak and almost weak stability of multiplication semigroups on Banach space‐valued ‐spaces. We show that, under certain conditions, these properties can be characterised by analogous ones of the pointwise semigroups. We prove a spectral mapping theorem for the point spectra of the pointwise and global semigroups and apply this as a major tool for determining almost weak stability. 相似文献
6.
J.M. Calabuig E.A. Sánchez Pérez 《Journal of Mathematical Analysis and Applications》2010,364(1):88-136
In order to extend the theory of optimal domains for continuous operators on a Banach function space X(μ) over a finite measure μ, we consider operators T satisfying other type of inequalities than the one given by the continuity which occur in several well-known factorization theorems (for instance, Pisier Factorization Theorem through Lorentz spaces, pth-power factorable operators …). We prove that such a T factorizes through a space of multiplication operators which can be understood in a certain sense as the optimal domain for T. Our extended optimal domain technique does not need necessarily the equivalence between μ and the measure defined by the operator T and, by using δ-rings, μ is allowed to be infinite. Classical and new examples and applications of our results are also given, including some new results on the Hardy operator and a factorization theorem through Hilbert spaces. 相似文献
7.
In this note, we analyse the relationship between the commutant of a bounded linear operator and the algebra of similarity that was introduced in the late 70s as a characterization of nest algebras. Necessary and sufficient conditions are also obtained for an operator to commute with real scalar generalized operators in the sense of Colojoara-Foias in Banach spaces. In the second part, we analyse the relationship between the generalized inverse, the generalized commutant and the orbits of conjugation.
8.
Continuous and compact Toeplitz operators for positive symbols are characterized on the space of analytic functions with logarithmic growth on the open unit disc of the complex plane. The characterizations are in terms of the behaviour of the Berezin transform of the symbol. The space was introduced and studied by Taskinen. The Bergman projection is continuous on this space in a natural way, which permits to define Toeplitz operators. Sufficient conditions for general symbols are also presented. 相似文献
9.
Anthony Conte Ege Fujikawa Nikola Lakic 《Proceedings of the American Mathematical Society》2007,135(10):3295-3300
We study Smale's mean value conjecture and its connection with the second coefficients of univalent functions. We improve the bound on Smale's constant given by Beardon, Minda and Ng.
10.
In the class of univalent bounded normalized holomorphic functions in the unit disk, we give an asymptotic estimate for the coefficients when the uniform norm of the modulus of the function tends to infinity. 相似文献
11.
The main objective of this work is to study generalized Browder's and Weyl's theorems for the multiplication operators LA and RB and for the elementary operator τAB=LARB. 相似文献
12.
王晓瑛 《纯粹数学与应用数学》2006,22(3):289-293
首先就Mbius变换在几何函数论上应用时存在的两个误区予以讨论,指出其存在的问题与如何改正;其次明确地指出用Baernstein方法估计m次对称单叶函数之逆函数系数时的不足之处;最后就S ingh与Puri一文中的一个结果给以改正,并用Ruschew eyh的共轭方法得到该结果成立的最佳范围. 相似文献
13.
We study composition operators, induced by a sub-domain of the unit disc whose boundary intersects the unit circle at 1 and which has, in a neighborhood of 1, a polar equation 1−r=γ(|θ|) (see Fig. 1). We obtain an explicit characterization for the membership in Schatten p-classes, in terms of γ. 相似文献
14.
B. Khani Robati 《Rendiconti del Circolo Matematico di Palermo》2000,49(3):601-608
Let ℬ be a Banach space of analytic functions defined on the open unit disk. We characterize the commutant ofM
Z
2 (the operator of multiplication by the square of independent variable defined on ℬ) and show that for an operatorS in the commutantM
Z
2 ifSM
Z
2k+1−M
Z
2k+1
S is compact for some nonnegative integerk, thenS=M
ϕ whereϕ is a multiplier of ℬ. Letn be a positive integer andS be an operator in the commutant ofM
Z
n defined on a functional Hilbert spaces of analytic functions. We show that under certain conditionsS has the formM
ϕ.
Research supported by the Shiraz University Grant 78-SC-1188-657. 相似文献
15.
Gelu Popescu 《Journal of Functional Analysis》2008,255(4):891-939
In this paper we initiate the study of sub-pluriharmonic curves and free pluriharmonic majorants on the noncommutative open ball
16.
Bebe Prunaru 《Proceedings of the American Mathematical Society》1996,124(11):3411-3412
Let be a pure hyponormal operator with compact self-commutator. We show that the unit ball of the commutant of is compact in the strong operator topology.
17.
Jesús de la Cal Javier Cárcamo 《Journal of Mathematical Analysis and Applications》2007,334(2):1106-1115
As a consequence of Jensen's inequality, centered operators of probabilistic type (also called Bernstein-type operators) approximate convex functions from above. Starting from this fact, we consider several pairs of classical operators and determine, in each case, which one is better to approximate convex functions. In almost all the discussed examples, the conclusion follows from a simple argument concerning composition of operators. However, when comparing Szász-Mirakyan operators with Bernstein operators over the positive semi-axis, the result is derived from the convex ordering of the involved probability distributions. Analogous results for non-centered operators are also considered. 相似文献
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20.
Let T∈Bn(H) be an essentially normal spherical isometry with empty point spectrum on a separable complex Hilbert space H, and let AT⊂B(H) be the unital dual operator algebra generated by T. In this note we show that every operator S∈B(H) in the essential commutant of AT has the form S=X+K with a T-Toeplitz operator X and a compact operator K. Our proof actually covers a larger class of subnormal operator tuples, called A-isometries, which includes for example the tuple T=(Mz1,…,Mzn)∈B(H2n(σ)) consisting of the multiplication operators with the coordinate functions on the Hardy space H2(σ) associated with the normalized surface measure σ on the boundary ∂D of a strictly pseudoconvex domain D⊂Cn. As an application we determine the essential commutant of the set of all analytic Toeplitz operators on H2(σ) and thus extend results proved by Davidson (1977) [6] for the unit disc and Ding and Sun (1997) [11] for the unit ball. 相似文献