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

Dmitri R. Yafaev

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.
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Cite this article as:
Dmitri R. Yafaev, Hankel and Toeplitz operators: continuous and discrete representations, Opuscula Math. 37, no. 1 (2017), 189-218, http://dx.doi.org/10.7494/OpMath.2017.37.1.189

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