Results 1 to 10 of about 36 (35)
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
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On hyponormality on a weighted annulus
Open Mathematics, 2021 In this work, we consider the hyponormality of Toeplitz operators on the Bergman space of the annulus with a logarithmic weight. We give necessary conditions when the symbol is of the form φ+ψ¯\varphi +\overline{\psi }, where φ\varphi and ψ\psi are ...
Sadraoui Houcine +2 more
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Spectra of Weighted Composition Operators with Quadratic Symbols
Concrete Operators, 2022 Previously, spectra of certain weighted composition operators W ѱ, φ on H2 were determined under one of two hypotheses: either φ converges under iteration to the Denjoy-Wolff point uniformly on all of 𝔻 rather than simply on compact subsets, or φ is ...
Doctor Jessica +4 more
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A derivative-Hilbert operator acting on Dirichlet spaces
Open Mathematics, 2023 Let μ\mu be a positive Borel measure on the interval [0,1)\left[0,1). The Hankel matrix Hμ=(μn,k)n,k≥0{{\mathcal{ {\mathcal H} }}}_{\mu }={\left({\mu }_{n,k})}_{n,k\ge 0} with entries μn,k=μn+k{\mu }_{n,k}={\mu }_{n+k}, where μn=∫[0,1)tndμ(t){\mu }_{n}={
Xu Yun, Ye Shanli, Zhou Zhihui
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Remarks on hyponormal Toeplitz operators with nonharmonic symbols
Open Mathematics, 2023 In this article, we present some necessary or sufficient conditions for the hyponormality of Toeplitz operator Tφ{T}_{\varphi } on the Bergman space A2(D){A}^{2}\left({\mathbb{D}}).
Kim Sumin, Lee Jongrak
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On unitary equivalence to a self-adjoint or doubly–positive Hankel operator
Concrete Operators, 2022 Let A be a bounded, injective and self-adjoint linear operator on a complex separable Hilbert space. We prove that there is a pure isometry, V, so that AV > 0 and A is Hankel with respect to V, i.e. V*A = AV, if and only if A is not invertible.
Martin Robert T.W.
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Eigenvalue asymptotics for a class of multi-variable Hankel matrices
Concrete Operators, 2023 A one-variable Hankel matrix Ha{H}_{a} is an infinite matrix Ha=[a(i+j)]i,j≥0{H}_{a}={\left[a\left(i+j)]}_{i,j\ge 0}. Similarly, for any d≥2d\ge 2, a dd-variable Hankel matrix is defined as Ha=[a(i+j)]{H}_{{\bf{a}}}=\left[{\bf{a}}\left({\bf{i}}+{\bf{j}})]
Tantalakis Christos Panagiotis
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On Determinant Expansions for Hankel Operators
Concrete Operators, 2020 Let w be a semiclassical weight that is generic in Magnus’s sense, and (pn)n=0∞({p_n})_{n = 0}^\infty the corresponding sequence of orthogonal polynomials. We express the Christoffel–Darboux kernel as a sum of products of Hankel integral operators.
Blower Gordon, Chen Yang
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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
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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
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