Volume 285, Issue 1 pp. 47-55
Research Article

Homogeneous polynomials and extensions of Hardy-Hilbert's inequality

Vasileios A. Anagnostopoulos

Corresponding Author

Vasileios A. Anagnostopoulos

School of Electrical and Computer Engineering, National Technical University, Zografou Campus 15780, Athens, Greece

Vasileios A. Anagnostopoulos, School of Electrical and Computer Engineering, National Technical University, Zografou Campus 15780, Athens, Greece, Phone: +30 210 867 9077, Fax: +30 210 7721775

Yannis Sarantopoulos, Department of Mathematics, National Technical University, Zografou Campus 15780, Athens, Greece, Phone: +30 210 772 1765, Fax: +30 210 772 1775

Andrew M. Tonge, Department of Mathematical Sciences, Kent State University, Kent OH 44242, USA, Phone: +1 330 672 9046, Fax: +1 330 672 2209

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Yannis Sarantopoulos

Corresponding Author

Yannis Sarantopoulos

Department of Mathematics, National Technical University, Zografou Campus 15780, Athens, Greece

Vasileios A. Anagnostopoulos, School of Electrical and Computer Engineering, National Technical University, Zografou Campus 15780, Athens, Greece, Phone: +30 210 867 9077, Fax: +30 210 7721775

Yannis Sarantopoulos, Department of Mathematics, National Technical University, Zografou Campus 15780, Athens, Greece, Phone: +30 210 772 1765, Fax: +30 210 772 1775

Andrew M. Tonge, Department of Mathematical Sciences, Kent State University, Kent OH 44242, USA, Phone: +1 330 672 9046, Fax: +1 330 672 2209

Search for more papers by this author
Andrew M. Tonge

Corresponding Author

Andrew M. Tonge

Department of Mathematical Sciences, Kent State University, Kent OH 44242, USA

Vasileios A. Anagnostopoulos, School of Electrical and Computer Engineering, National Technical University, Zografou Campus 15780, Athens, Greece, Phone: +30 210 867 9077, Fax: +30 210 7721775

Yannis Sarantopoulos, Department of Mathematics, National Technical University, Zografou Campus 15780, Athens, Greece, Phone: +30 210 772 1765, Fax: +30 210 772 1775

Andrew M. Tonge, Department of Mathematical Sciences, Kent State University, Kent OH 44242, USA, Phone: +1 330 672 9046, Fax: +1 330 672 2209

Search for more papers by this author
First published: 08 September 2011
Citations: 1

Abstract

If L is a continuous symmetric n-linear form on a real or complex Hilbert space and \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\widehat{L}$\end{document}equation image is the associated continuous n-homogeneous polynomial, then \documentclass{article}\usepackage{amssymb}\begin{document}\pagestyle{empty}$\Vert L\Vert =\big \Vert \widehat{L}\big \Vert$\end{document}equation image. We give a simple proof of this well-known result, which works for both real and complex Hilbert spaces, by using a classical inequality due to S. Bernstein for trigonometric polynomials. As an application, an open problem for the optimal lower bound of the norm of a homogeneous polynomial, which is a product of linear forms, is related to the so-called permanent function of an n × n positive definite Hermitian matrix. We have also derived generalizations of Hardy-Hilbert's inequality.

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