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ESTIMATES OF GENERALIZED EIGENVECTORS OF HERMITIAN JACOBI MATRICES WITH A GAP IN THE ESSENTIAL SPECTRUM

Published online by Cambridge University Press:  14 May 2012

J. Janas
Affiliation:
Institute of Mathematics PAN, 31-027 Cracow, Poland (email: najanas@cyf-kr.edu.pl)
S. Naboko
Affiliation:
Department of Mathematical Physics, Institute of Physics, St. Petersburg, 198904, Russia (email: naboko@snoopy.phys.spbu.ru)
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Abstract

In this paper we prove sharp estimates for generalized eigenvectors of Hermitian Jacobi matrices associated with the spectral parameter lying in a gap of their essential spectra. The estimates do not depend on the main diagonals of these matrices. The types of estimates obtained for bounded and unbounded gaps are different. These estimates extend the previous ones found in [J. Janas, S. Naboko and G. Stolz, Decay bounds on eigenfunctions and the singular spectrum of unbounded Jacobi matrices. Int. Math. Res. Not.4 (2009), 736–764], for the spectral parameter being outside the whole spectrum of Jacobi matrices. Examples illustrating optimality of our results are also given.

Type
Research Article
Copyright
Copyright © University College London 2012

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