Results 11 to 20 of about 830 (68)

Mean Lipschitz spaces and a generalized Hilbert operator [PDF]

, 2017
If $\mu $ is a positive Borel measure on the interval $[0, 1)$ we let $\mathcal H_\mu $ be the Hankel matrix $\mathcal H_\mu =(\mu _{n, k})_{n,k\ge 0}$ with entries $\mu _{n, k}=\mu _{n+k}$, where, for $n\,=\,0, 1, 2, \dots $, $\mu_n$ denotes the moment ...
Merchán, Noel
core   +2 more sources

A lower bound in Nehari's theorem on the polydisc [PDF]

, 2011
By theorems of Ferguson and Lacey (d=2) and Lacey and Terwilleger (d>2), Nehari's theorem is known to hold on the polydisc D^d for d>1, i.e., if H_\psi is a bounded Hankel form on H^2(D^d) with analytic symbol \psi, then there is a function \phi in L ...
H. Helson, H. Helson, Joaquim Ortega-Cerdà, Kristian Seip, M. Lacey, M. Lacey, S. Ferguson, Z. Nehari   +7 more
core   +3 more sources

Functions of self‐adjoint operators in ideals of compact operators

Journal of the London Mathematical Society, Volume 95, Issue 1, Page 157-176, February 2017., 2017
Abstract For self‐adjoint operators A,B, a bounded operator J, and a function f:R→C, we obtain bounds in quasi‐normed ideals of compact operators for the difference f(A)J−Jf(B) in terms of the operator AJ−JB. The focus is on functions f that are smooth everywhere except for finitely many points. A typical example is the function f(t)=|t|γ with γ∈(0,1).
Alexander V. Sobolev
wiley   +1 more source

Schatten Class Operators in ℒ(La2(ℂ+))\msbm=MTMIB${\cal L}\left( {L_a^2 \left( {{\msbm C}_+ } \right)} \right)$

Annals of the West University of Timisoara: Mathematics and Computer Science, 2017
In this paper, we consider Toeplitz operators defined on the Bergman space La2(ℂ+)\msbm=MTMIB$L_a^2 \left( {{\msbm C}_+ } \right)$ of the right half plane and obtain Schatten class characterization of these operators. We have shown that if the Toeplitz
Das Namita, Behera Jitendra Kumar
doaj   +1 more source

Localization of compactness of Hankel operators on pseudoconvex domains [PDF]

, 2011
We prove the following localization for compactness of Hankel operators on Bergman spaces. Assume that D is a bounded pseudoconvex domain in C^n, p is a boundary point of D and B(p,r) is a ball centered at p with radius r so that U=D\cap B(p,r) is ...
Sahutoglu, Sonmez
core   +1 more source

Lipschitz estimates for the Berezin transform

Journal of Function Spaces, Volume 8, Issue 2, Page 103-128, 2010., 2010
We consider the generalized Fock space A2(μm), where μm is the measure with weight e−|z|m, m > 0, with respect to the Lebesgue measure on Cn. Improving upon a recent result of L. Coburn and J. Xia, we show that for any bounded operator X on A2(μm) , the Berezin transform of X satisfies Lipschitz estimates.
Hélène Bommier-Hato, Miroslav Engliš
wiley   +1 more source

The Weiss conjecture on admissibility of observation operators for contraction semigroups [PDF]

, 2001
We prove the conjecture of George Weiss for contraction semigroups on Hilbert spaces, giving a characterization of infinite-time admissible observation functionals for a contraction semigroup, namely that such a functional C is infinite-time admissible ...
A. Simard, B. Sz. Nagy, Birgit Jacob, E.B. Davies, E.W. Packel, F.F. Bonsall, F.F. Bonsall, G. Weiss, J.R. Partington, Jonathan R. Partington, O. Blasco, P. Grabowski, P. Koosis, Y. Meyer   +13 more
core   +1 more source

Volterra composition operators from generalized weighted weighted Bergman spaces to µ‐Bloch spaces

Journal of Function Spaces, Volume 7, Issue 3, Page 225-240, 2009., 2009
Let φ be a holomorphic self‐map and g be a fixed holomorphic function on the unit ball B. The boundedness and compactness of the operator Tg,φf(z)=∫01f(φ(tz))ℜg(tz)dtt from the generalized weighted Bergman space into the µ‐Bloch space are studied in this paper.
Xiangling Zhu
wiley   +1 more source

A new class of linear operators on ℓ2 and Schur multipliers for them

Journal of Function Spaces, Volume 5, Issue 2, Page 151-165, 2007., 2007
We introduce the space Bw(ℓ2) of linear (unbounded) operators on ℓ2 which map decreasing sequences from ℓ2 into sequences from ℓ2 and we find some classes of operators belonging either to Bw(ℓ2) or to the space of all Schur multipliers on Bw(ℓ2). For instance we show that the space B(ℓ2) of all bounded operators on ℓ2 is contained in the space of all ...
Anca-Nicoleta Marcoci, Liviu-Gabriel Marcoci, Nicolae Popa   +2 more
wiley   +1 more source

Weighted integral Hankel operators with continuous spectrum

Concrete Operators, 2017
Using the Kato-Rosenblum theorem, we describe the absolutely continuous spectrum of a class of weighted integral Hankel operators in L2(ℝ+). These self-adjoint operators generalise the explicitly diagonalisable operator with the integral kernel sαtα(s ...
Fedele Emilio, Pushnitski Alexander
doaj   +1 more source