Results on the existence and convergence of best proximity points.
A Riesz representation formula for super-biharmonic functions.
Computation of Biharmonic Poisson Kernel for the Upper Half Plane
We first consider the biharmonic Poisson kernel for the unit disk, and study the boundary behavior of potentials associated to this kernel function. We shall then use some properties of the biharmonic Poisson kernel for the unit disk to compute the analogous biharmonic Poisson kernel for the upper half plane.
Commutant of multiplication operators in weighted Bergman spaces on polydisk
We study a certain operator of multiplication by monomials in the weighted Bergman space both in the unit disk of the complex plane and in the polydisk of the -dimensional complex plane. Characterization of the commutant of such operators is given.
On the integral representation of superbiharmonic functions
We consider a nonnegative superbiharmonic function satisfying some growth condition near the boundary of the unit disk in the complex plane. We shall find an integral representation formula for in terms of the biharmonic Green function and a multiple of the Poisson kernel. This generalizes a Riesz-type formula already found by the author for superbihamonic functions satisfying the condition in the unit disk. As an application we shall see that the polynomials are dense in weighted Bergman...
Polyanalytic Besov spaces and approximation by dilatations
Using partial derivatives and , we introduce Besov spaces of polyanalytic functions in the open unit disk, as well as in the upper half-plane. We then prove that the dilatations of functions in certain weighted polyanalytic Besov spaces converge to the same functions in norm. When restricted to the open unit disk, we prove that each polyanalytic function of degree can be approximated in norm by polyanalytic polynomials of degree at most .
Invariant subspaces on multiply connected domains.
The lattice of invariant subspaces of several Banach spaces of analytic functions on the unit disk, for example the Bergman spaces and the Dirichlet spaces, have been studied recently. A natural question is to what extent these investigations carry over to analogously defined spaces on an annulus. We consider this question in the context of general Banach spaces of analytic functions on finitely connected domains Ω. The main result reads as follows: Assume that B is a Banach space of analytic functions...
Weighted sub-Bergman Hilbert spaces in the unit disk
We study sub-Bergman Hilbert spaces in the weighted Bergman space . We generalize the results already obtained by Kehe Zhu for the standard Bergman space .
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