Results 51 to 60 of about 956 (81)

Jointly hyponormal block Toeplitz pairs with rational symbols

, 2018
In this paper, we are concerned with joint hyponormality of pairs of block Toeplitz operators acting on the vector-valued Hardy space H2 Cn of the unit circle.
I. Hwang, An-Hyun Kim
semanticscholar   +1 more source

A subnormal Toeplitz completion

, 2016
In this paper we deal with a subnormal Toeplitz completion problem: Complete the unspecified Toeplitz operators of the partial block Toeplitz matrix G := [ U∗p ? ? U∗q ] (p,q = 1,2, · · ·) to make G subnormal, where U is the shift on the Hardy space H2(T)
I. Hwang, An-Hyun Kim, Jongrak Lee
semanticscholar   +1 more source

On semibounded Toeplitz operators

, 2016
We show that a semibounded Toeplitz quadratic form is closable in the space $\ell^2({\Bbb Z}_{+})$ if and only if its matrix elemens are Fourier coefficients of an absolutely continuous measure.
Yafaev, D. R.
core   +3 more sources

A note on the Fredholm properties of Toeplitz operators on weighted Bergman spaces with matrix-valued symbols

, 2011
We characterize the essential spectra of Toeplitz operators Ta on weighted Bergman spaces with matrix-valued symbols; in particular we deal with two classes of symbols, the Douglas algebra C+H∞ and the Zhu class Q := L∞ ∩VMO∂ . In addition, for symbols
A. Perälä, J. Virtanen
semanticscholar   +1 more source

Harmonic analysis on the quantized Riemann sphere

, 1993
International Journal of Mathematics and Mathematical Sciences, Volume 16, Issue 2, Page 225-243, 1993.
Jaak Peetre, Genkai Zhang
wiley   +1 more source

Unbounded Hankel operators and moment problems

, 2019
We find simple conditions for a non-negative Hankel quadratic form to be closable. Under some mild a priori assumption on the associated moments these sufficient conditions turn out to be also necessary.
Yafaev, D. R.
core   +3 more sources

Boundary integral methods for wedge diffraction problems: the angle 2π/n, Dirichlet and Neumann conditions

, 2011
In this paper we use analytical methods for boundary integral operators (more precisely, pseudodifferential operators) together with symmetry arguments in order to treat harmonic wave diffraction problems in which the field does not depend on the third ...
T. Ehrhardt, A. P. Nolasco, F. Speck
semanticscholar   +1 more source

The weighted composition operators on the large weighted Bergman spaces

, 2018
In this paper, we characterize bounded, compact or Schatten class weighted composition operators acting on Bergman spaces with the exponential type weights. Moreover, we give the proof of the necessary part for the boundedness of composition operators on
Park, Inyoung
core   +1 more source

A transmission problem for the Helmholtz equation with higher order boundary conditions

, 2015
The present paper deals with some properties for certain classes of Wiener-Hopf operators associated with a wave diffraction problem. This diffraction problem is mathematically modeled by the Helmholtz equation and higher order boundary conditions on an ...
Alberto Simões
semanticscholar   +1 more source

Introduction to the dynamical properties of Toeplitz operators on the Hardy space of the unit disc

Concrete Operators
These notes are based on a mini-course given at the ACOTCA conference 2025. The goal is to present full proofs of the first two key results regarding hypercyclic Toeplitz operators, in a way that is accessible to beginners.
Fricain Emmanuel, Ostermann Maëva
doaj   +1 more source