Hankel and Toeplitz operators: continuous and discrete representations

We find a relation guaranteeing that Hankel operators realized in the space of sequences \(\mathcal{l}^2 (\mathbb{Z}_{+})\) and in the space of functions \(L^2 (\mathbb{R}_{+})\) are unitarily equivalent. This allows us to obtain exhaustive spectral results for two classes of unbounded Hankel operat...

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Bibliographic Details
Main Author: Dmitri R. Yafaev
Format: Article
Language:English
Published: AGH Univeristy of Science and Technology Press 2017-01-01
Series:Opuscula Mathematica
Subjects:
Online Access:http://www.opuscula.agh.edu.pl/vol37/1/art/opuscula_math_3708.pdf
Description
Summary:We find a relation guaranteeing that Hankel operators realized in the space of sequences \(\mathcal{l}^2 (\mathbb{Z}_{+})\) and in the space of functions \(L^2 (\mathbb{R}_{+})\) are unitarily equivalent. This allows us to obtain exhaustive spectral results for two classes of unbounded Hankel operators in the space \(\mathcal{l}^2 (\mathbb{Z}_{+})\) generalizing in different directions the classical Hilbert matrix. We also discuss a link between representations of Toeplitz operators in the spaces \(\mathcal{l}^2 (\mathbb{Z}_{+})\) and \(L^2 (\mathbb{R}_{+})\).
ISSN:1232-9274