双圆盘上Hardy空间上Hankel 算子和Toeplitz 算子的交换性

In this paper, we characterize when the Toeplitz operator Tf and the Hankel operator Hg commute on the Hardy space of the bidisk. For certain types of bounded symbols f and g, we give a necessary and sufficient condition on the symbols to guarantee TfHg = HgTf.     

Double Commuting Compressed Shifts and Generalized Interpolation in the Hardy Space over the Bidisk

This paper deals with an operator theory of compressed shifts on the Hardy space over the bidisk. We give commutant lifting type theorems and some interpolation theorems in two variables.     

Parametrized Area Integrals on Hardy Spaces and Weak Hardy Spaces

In this paper, the authors prove that if Ω satisfies a class of the integral Dini condition, then the parametrized area integral μΩ,S^ρ is a bounded operator from the Hardy space H1 （R^n） to L1 （R^n） and from the weak Hardy space H^1,∞ （R^n） to L^1,∞ （R^n）, respectively. As corollaries of the above results, it is shown that μΩ,S^ρ is also an operator of weak type These conclusions are substantial improvement and （1, 1） and of type （p,p） for 1 〈 p 〈 2, respectively extension of some known results.     

Discrete Hardy Spaces

We study the boundary behavior of discrete monogenic functions, i.e. null-solutions of a discrete Dirac operator, in the upper and lower half space. Calculating the Fourier symbol of the boundary operator we construct the corresponding discrete Hilbert transforms, the projection operators arising from them, and discuss the notion of discrete Hardy spaces. Hereby, we focus on the 3D-case with the generalization to the n-dimensional case being straightforward.     

Topological Structure of the Space of Weighted Composition Operators Between Different Hardy Spaces

We consider properties related to weighted composition operators boundedly acting from the classical Hardy space H ^p to H ^q for \({1 \leq q < p < \infty}\) . Especially, we shall completely determine path connected components in the set of weighted composition operators and explicitly characterize by function-theoretic properties of analytic self-maps.     

Hardy空间的乘子

本文刻划了Hardy空间H^p（1≤p≤∞）到Bloch空间的乘子,推广了前人的结果。     

调和H~p空间和混合范数空间

设Ｄ是一具有Ｃ边界的有界区域．本文就Ｄ上的调和Ｈａｒｄｙ空间和调和混合范数空间,建立了若干互相之间的连续嵌入定理．     

On Multipliers in Hardy Spaces

We investigate the accuracy of certain sufficient conditions for multipliers of power series in Hardy spaces.     

Hilbert空间中的K-框架

K-框架是框架理论的一种推广.K-框架可以用于重构Hilbert空间中有界线性算子值域内的元素.本文首先研究了K-框架与框架理论的关系,得到了紧K-框架成为框架当且仅当有界线性算子K是满的,给出了有界线性算子K具有闭值域的K-框架的一个充要条件.并利用有界线性算子K和合成算子构造K-框架,讨论在一定扰动条件下K-框架的稳定性.     

Anisotropic Local Hardy Spaces

In this paper we introduce and study the anisotropic local Hardy spaces h_A^p(\mathbbRⁿ)h_{A}^{p}(\mathbb{R}^{n}) 0<p≤1, associated with the expansive matrix A. We obtain an atomic characterization of the distributions in h_A^p(\mathbbRⁿ)h_{A}^{p}(\mathbb{R}^{n}). Also we describe the dual spaces of our local Hardy anisotropic spaces as anisotropic Campanato type spaces.     

Anisotropic Mixed-Norm Hardy Spaces

We introduce and explore Hardy spaces defined by mixed Lebesgue norms and anisotropic dilations. We prove that the definitions of these spaces in terms of smooth, non-tangential, auxiliary, grand, and Poisson maximal operators coincide. We also study the relation between anisotropic mixed-norm Hardy spaces and mixed-norm Lebesgue spaces.     

Hardy空间的等价刻画

设Ｇ为局部域Ｋ上的２ｎ＋１维Ｈｅｉｓｅｎｂｅｒｇ群．本文证明了通过各种极大函数定义的Ｈａｒｄｙ空间的等价性，给出了Ｈａｒｄｙ空间的原子分解．利用这些等价定义及一些卷积算子定理，给出了Ｈａｒｄｙ空间的平方函数刻画——Ｌｕｚｉｎ面积函数刻画与Ｌｉｔｌｅｗｏｏｄ－Ｐａｌｅｙ平方函数刻画     

Approximate Factorization in Generalized Hardy Spaces

In this paper we establish a connection between the approximate factorization property appearing in the theory of dual algebras and the spectral inclusion property for a class of Toeplitz operators on Hilbert spaces of vector valued square integrable functions. As an application, it follows that a wide range of dual algebras of subnormal Toeplitz operators on various Hardy spaces associated to function algebras have property (A ₁(1)). It is also proved that the dual algebra generated by a spherical isometry (with a possibly infinite number of components) has the same property. One particular application is given to the existence of unimodular functions sitting in cyclic invariant subspaces of weak* Dirichlet algebras. Moreover, by this method we provide a unified approach to several Toeplitz spectral inclusion theorems. Research partially supported by grant CNCSIS GR202/2006 (cod 813).     

Monsters in Hardy and Bergman Spaces

A monster in the sense of Luh is a holomorphic function on a simply connected domain in the complex plane such that it and all its derivatives and antiderivatives exhibit an extremely wild behaviour near the boundary. In this paper, the Hardy spaces H p and the Bergman spaces B p (1 h p < X ) on the unit disk are considered, and it is shown that there are no Luh-monsters in them. Nevertheless, it is proved that T -monsters (as introduced by the authors in an earlier work) can be found in each of these spaces for any finite order linear differential operator T .     

Real Functions in Weighted Hardy Spaces

We study the following problem: to describe weights w on the unit circle such that the analytic and antianalytic subspaces of the corresponding weighted space ^Lp(w) have nonzero intersection. In the special case p=2, the problem is equivalent to the well-known problem on exposed points in H ¹. We show that the property in question is local, i.e., it depends on local behavior of the weight w at each point of the unit circle. Some necessary and sufficient conditions in terms of the Herglotz integrals are obtained. Bibliography: 6 titles.     

Scalar Derivatives in Hilbert Spaces

Computational formulae for scalar derivatives of mappings and pairs of mappings in the direction of a set will be given. These formulae are very important for explicitly verifying conditions of existence for fixed point theorems, surjectivity theorems, integral equations, variational inequalities and complementarity problems under additional differentiability conditions. To emphasize this idea at the end of the paper we give an application to complementarity problems. Some theorems which extend the correspondence between monotone mappings and scalar derivatives from Euclidean spaces to Hilbert spaces will also be given.     

Hilbert空间中的紧K-框架

K-框架是框架的一种推广.本文在Hilbert空间将紧框架推广到K-框架上,引入紧K-框架的概念.通过紧K-框架的算子K和合成算子给出紧K-框架的算子刻画,并利用紧K-框架的算子K给出紧K-框架成为紧框架的一个充要条件.还讨论紧K-框架的构造以及两个紧K-框架集的包含与涉及的算子K的相互关系.     

Hardy空间到Zygmund型空间的Riemann-Stieltjes算子

利用Hardy空间中函数的高阶导数的估计,通过构造一些新的检验函数,运用解析函数的性质与算子理论,给出了从Hardy空间到Zygmund型空间的Riemann—Stieltjes算子的有界性和紧性的特征,获得了若干个充要条件.     

Uncertainty Principles in Hilbert Spaces

In this article we provide several generalizations of inequalities bounding the commutator of two linear operators acting on a Hilbert space which relate to the Heisenberg uncertainty principle and time/frequency analysis of periodic functions. We develop conditions that ensure these inequalities are sharp and apply our results to concrete examples of importance in the literature.