Opuscula Math. 37, no. 1 (2017), 189-218
http://dx.doi.org/10.7494/OpMath.2017.37.1.189
Opuscula Mathematica
Hankel and Toeplitz operators: continuous and discrete representations
Abstract. 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 \(L^2 (\mathbb{R}_{+})\).
Keywords: unbounded Hankel and Toeplitz operators, various representations, moment problems, generalized Hilbert matrices.
Mathematics Subject Classification: 47B25, 47B35.
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- Dmitri R. Yafaev
- Université de Rennes I, IRMAR, Campus de Beaulieu, 35042 Rennes Cedex, France
- Communicated by P.A. Cojuhari.
- Received: 2016-07-11.
- Revised: 2016-09-23.
- Accepted: 2016-09-25.
- Published online: 2016-12-14.
