Results 1 to 10 of about 391 (23)
Exterior products of operators and superoptimal analytic approximation
Transactions of the London Mathematical Society, 2021 We give a new algorithm for the construction of the unique superoptimal analytic approximant of a given continuous matrix‐valued function on the unit circle, using exterior powers of operators in preference to spectral or Wiener–Masani factorizations.
Dimitrios Chiotis +2 more
doaj +1 more source
Generalized Crofoot transform and applications
Concrete Operators, 2023 Matrix-valued asymmetric truncated Toeplitz operators are compressions of multiplication operators acting between two model spaces. These are the generalization of matrix-valued truncated Toeplitz operators. In this article, we describe symbols of matrix-
Khan Rewayat, Farooq Aamir
doaj +1 more source
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
On the weak limit of compact operators on the reproducing kernel Hilbert space and related questions
Analele Stiintifice ale Universitatii Ovidius Constanta: Seria Matematica, 2016 By applying the so-called Berezin symbols method we prove a Gohberg- Krein type theorem on the weak limit of compact operators on the non- standard reproducing kernel Hilbert space which essentially improves the similar results of Karaev [5]: We also in ...
Saltan Suna
doaj +1 more source
A hyperbolic universal operator commuting with a compact operator [PDF]
, 2019 A Hilbert space operator is called universal (in the sense of Rota) if every operator on the Hilbert space is similar to a multiple of the restriction of the universal operator to one of its invariant subspaces.
Cowen, Carl C. +1 more
core +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 +13 more
core +1 more source
A Hankel matrix acting on spaces of analytic functions [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 ...
Girela, Daniel, Merchán, Noel
core +2 more sources
Closable Hankel operators and moment problems
, 2019 In a paper from 2016 D. R. Yafaev considers Hankel operators associated with Hamburger moment sequences q_n and claims that the corresponding Hankel form is closable if and only if the moment sequence tends to 0.
Berg, Christian, Szwarc, Ryszard
core +1 more source
Toeplitz Operators on Weighted Bergman Spaces [PDF]
, 2012 In this article we characterize the boundedness and compactness of a Toeplitz-type operator on weighted Bergman spaces satisfying the so-called Bekolle-Bonami condition in terms of the Berezin ...
Chacón, Gerardo R.
core +3 more sources
On compactness of the dbar-Neumann problem and Hankel operators
, 2011 Let $\D=\D_1\setminus \Dc_2$, where $\D_1$ and $\D_2$ are two smooth bounded pseudoconvex domains in $\C^n, n\geq 3,$ such that $\Dc_2\subset \D_1.$ Assume that the $\dbar$-Neumann operator of $\D_1$ is compact and the interior of the Levi-flat points in
Celik, Mehmet, Sahutoglu, Sonmez
core +1 more source