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JOURNALS // Funktsional'nyi Analiz i ego Prilozheniya // Archive

Funktsional. Anal. i Prilozhen., 2007 Volume 41, Issue 2, Pages 78–92 (Mi faa2862)

This article is cited in 3 papers

Meromorphic Jost Functions and Asymptotic Expansions for Jacobi Parameters

B. Simon

California Institute of Technology

Abstract: We show that the parameters $a_n$, $b_n$ of a Jacobi matrix have a complete asymptotic expansion
$$ a_n^2-1=\sum_{k=1}^{K(R)} p_k(n) \mu_k^{-2n}+ O(R^{-2n}),\qquad b_n=\sum_{k=1}^{K(R)} p_k(n)\mu_k^{-2n+1}+O(R^{-2n}), $$
where $1<|\mu_j|<R$ for $j\le K(R)$ and all $R$, if and only if the Jost function, $u$, written in terms of $z$ (where $E=z+z^{-1}$) is an entire meromorphic function. We relate the poles of $u$ to the $\mu_j$'s.

Keywords: Jost function, Jacobi matrix, exponential decay.

UDC: 517.98

Received: 12.05.2006

DOI: 10.4213/faa2862


 English version:
Functional Analysis and Its Applications, 2007, 41:2, 143–153

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