On positive Jacobi matrices with compact inverses

Fuente: arXiv
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Auteurs principaux: Šťovíček, Pavel, Świderski, Grzegorz
Format: Preprint
Publié: 2024
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author Šťovíček, Pavel
Świderski, Grzegorz
author_facet Šťovíček, Pavel
Świderski, Grzegorz
contents We consider positive Jacobi matrices $J$ with compact inverses and consequently with purely discrete spectra. A number of properties of the corresponding sequence of orthogonal polynomials is studied including the convergence of their zeros, the vague convergence of the zero counting measures and of the Christoffel--Darboux kernels on the diagonal. Particularly, if the inverse of $J$ belongs to some Schatten class, we identify the asymptotic behaviour of the sequence of orthogonal polynomials and express it in terms of its regularized characteristic function. In the even more special case when the inverse of $J$ belongs to the trace class we derive various formulas for the orthogonality measure, eigenvectors of $J$ as well as for the functions of the second kind and related objects. These general results are given a more explicit form in the case when $-J$ is a generator of a Birth--Death process. Among others we provide a formula for the trace of the inverse of $J$. We illustrate our results by introducing and studying a modification of $q$-Laguerre polynomials corresponding to a determinate moment problem.
format Preprint
id arxiv_https___arxiv_org_abs_2409_19644
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On positive Jacobi matrices with compact inverses
Šťovíček, Pavel
Świderski, Grzegorz
Spectral Theory
Classical Analysis and ODEs
47B36 (Primary) 42C05, 33C45 (Secondary)
We consider positive Jacobi matrices $J$ with compact inverses and consequently with purely discrete spectra. A number of properties of the corresponding sequence of orthogonal polynomials is studied including the convergence of their zeros, the vague convergence of the zero counting measures and of the Christoffel--Darboux kernels on the diagonal. Particularly, if the inverse of $J$ belongs to some Schatten class, we identify the asymptotic behaviour of the sequence of orthogonal polynomials and express it in terms of its regularized characteristic function. In the even more special case when the inverse of $J$ belongs to the trace class we derive various formulas for the orthogonality measure, eigenvectors of $J$ as well as for the functions of the second kind and related objects. These general results are given a more explicit form in the case when $-J$ is a generator of a Birth--Death process. Among others we provide a formula for the trace of the inverse of $J$. We illustrate our results by introducing and studying a modification of $q$-Laguerre polynomials corresponding to a determinate moment problem.
title On positive Jacobi matrices with compact inverses
topic Spectral Theory
Classical Analysis and ODEs
47B36 (Primary) 42C05, 33C45 (Secondary)
url https://arxiv.org/abs/2409.19644