单位球Dirichlet空间上的交换对偶Toeplitz算子

研究对偶Toeplitz算子（半）交换时其符号的关系.通过对其符号的分解,借助多复变函数的有关理论,得到了单位球Dirichlet空间上以多重调和函数为符号的对偶Toeplitz算子Sψ与Sψ（半）交换的充要条件.     

Linear fractional composition operators on the Dirichlet space in the unit ball

We investigate the adjoints of linear fractional composition operators Cφ acting on classical Dirichlet space D(BN ) in the unit ball BN of CN , and characterize the normality and essential normality of Cφ on D(BN ) and the Dirichlet space modulo constant function D0(BN ), where φ is a linear fractional map of BN . In addition, we also show that for any non-elliptic linear fractional map φ of BN , the composition maps σ ο φ and φ ο σ are elliptic or parabolic linear fractional maps of BN .     

Toeplitz operators with BMO symbols on the weighted Bergman space of the unit ball

In this paper we prove that the boundedness and compactness of Toeplitz operator with a BMO _α ¹ symbol on the weighted Bergman space A _α ²(B _n ) of the unit ball is completely determined by the behavior of its Berezin transform, where α > −1 and n ≥ 1.     

Dirichlet型空间的Carleson测度和乘子

设0-1,D_α~p表示单位球B_n上满足∫_(B_n)(1-|z|~2)~α|▽f(z)|~pdv(z)<∞的全纯函数全体.对0相似文献   

The pointwise multipliers of Bloch type space β and Dirichlet type space Dq on the unit ball of C

In the paper, we will discuss the pointwise multipliers from Dirichlet type space D_p to Bloch type space β^q on the unit ball of Cⁿ. The multiplier spaces M(D_p,β^q) are fully characterized for all p, q.     

Toeplitz products with pluriharmonic symbols on the Hardy space over the ball

On the Hardy space over the unit ball in Cn, we consider operators which have the form of a finite sum of products of several Toeplitz operators. We study characterizing problems of when such an operator is compact or of finite rank. Some of our results show higher-dimensional phenomena.     

Hardy space interpolation in the unit ball

Interpolating sequences for the spaces H^p(Bⁿ), 1 <-p < ∞, n≥2, are studied. In contrast to the case n = 1, they are not the same for all p, but Varopoulos' necessary condition for H^∞ interpolation turns out to be necessary for H^p interpolation, for any p≥ 1, and sufficient for the sequence to be a finite union of H¹ interpolating sequences. Sufficient conditions are given for H^p interpolation, npn/(n-1), which are intermediary between Varopoulos' condition and Berndtsson's sufficient condition for H^∞(Bⁿ) interpolation.     

Riemann-Hilbert problems for poly-Hardy space on the unit ball

In this paper, we focus on a Riemann–Hilbert boundary value problem (BVP) with a constant coefficients for the poly-Hardy space on the real unit ball in higher dimensions. We first discuss the boundary behaviour of functions in the poly-Hardy class. Then we construct the Schwarz kernel and the higher order Schwarz operator to study Riemann–Hilbert BVPs over the unit ball for the poly-Hardy class. Finally, we obtain explicit integral expressions for their solutions. As a special case, monogenic signals as elements in the Hardy space over the unit sphere will be reconstructed in the case of boundary data given in terms of functions having values in a Clifford subalgebra. Such monogenic signals represent the generalization of analytic signals as elements of the Hardy space over the unit circle of the complex plane.     

On a class of Riccati equations in a Hilbert space

We establish existence and uniqueness of solutions of a class of Riccati equations in Hilbert space ocurring in filtering problems for distributed parameter systems using point sensors.     

Riccati type transformations for second-order linear difference equations

Oscillation and comparison theorems for a linear homogeneous second-order difference equation are proved by employing various equivalent non-linear equations obtained by means of transformations analogous to the Riccati transformation for ordinary differential equations.     

Hankel operators on the Bergman space of the unit ball

We characterize the bounded holomorphic functions in the unit ball of for which the operator is compact. For the result was obtained by Axler and Gorkin in 1988 and by Zheng in 1989.

     

Infinity-Laplacian type equations and their associated Dirichlet problems

ABSTRACT

In this paper, we study the Dirichlet problem associated with infinity-Laplacian type equations that may exhibit anisotropic character. We identify a broad class of nonlinearities for which the problem may or may not admit viscosity solutions for any continuous boundary data. We also discuss comparison with Finsler cones, which may be of independent interest.     

Half Dirichlet problem for matrix functions on the unit ball in Hermitian Clifford analysis

The simultaneous null solutions of the two complex Hermitian Dirac operators are focused on in Hermitian Clifford analysis, where the Hermitian Cauchy integral was constructed and will play an important role in the framework of circulant (2×2) matrix functions. Under this setting we will present the half Dirichlet problem for circulant (2×2) matrix functions on the unit ball of even dimensional Euclidean space. We will give the unique solution to it merely by using the Hermitian Cauchy transformation, get the solution to the Dirichlet problem on the unit ball for circulant (2×2) matrix functions and the solution to the classical Dirichlet problem as the special case, derive a decomposition of the Poisson kernel for matrix Laplace operator, and further obtain the decomposition theorems of solution space to the Dirichlet problem for circulant (2×2) matrix functions.     

Existence and comparison theorems for partial differential equations of Riccati type

In this paper, we discuss the partial differential equation of Riccati type that describes the optimal filtering error covariance function for a linear distributed-parameter system with pointwise observations. Since this equation contains the Dirac delta function, it is impossible to apply directly the usual methods of functional analysis to prove existence and uniqueness of a bounded solution. By using properties of the fundamental solution and the classical technique of successive approximation, we prove the existence and uniqueness theorem. We then prove the comparison theorem for partial differential equations of Riccati type. Finally, we consider some applications of these theorems to the distributed-parameter optimal sensor location problem.     

A new Banach space with Valdivia dual unit ball

We give an example of a Banach space which admits no projectional resolution of the identity but whose dual unit ball in weak* topology is a Valdivia compact. This answers a question asked by M. Fabian, G. Godefroy and V. Zizler. Partially supported by Research grants GAUK 277/2001, GAUK 160/1999 and MSM 113200007.     

On convergence on the boundary of the unit ball in dual space

In this paper some results that are known for extreme points of the unit ball in dual space are carried over to a more general case, namely to the case of the boundary of the ball ( B is the boundary of the unit ballB in the space dual toX if everyx X achieves its maximum value onB at some point of ). For example, it is established that if a set is bounded inX and countably compact in(X, ), then it is weakly compact inX.Translated fromMatematickeskie Zametki, Vol. 59, No. 5, pp. 753–758, May, 1996.