Nonnegative extensions of Sturm-Liouville operators with an application to problems with symmetric coefficient functions

Fuente: arXiv
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Main Authors: Fischbacher, Christoph, Stanfill, Jonathan
Format: Preprint
Published: 2024
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author Fischbacher, Christoph
Stanfill, Jonathan
author_facet Fischbacher, Christoph
Stanfill, Jonathan
contents The purpose of this paper is to study nonnegative self-adjoint extensions associated with singular Sturm-Liouville expressions with strictly positive minimal operators. We provide a full characterization of all possible nonnegative self-adjoint extensions of the minimal operator in terms of generalized boundary values, as well as a parameterization of all nonnegative extensions when fixing a boundary condition at one endpoint. In addition, we investigate problems where the coefficient functions are symmetric about the midpoint of a finite interval, illustrating how every self-adjoint operator of this form is unitarily equivalent to the direct sum of two self-adjoint operators restricted to half of the interval. We also extend these result to symmetric two interval problems. We then apply our previous results to parameterize all nonnegative extensions of operators with symmetric coefficient functions. We end with an example of an operator with a symmetric Bessel-type potential (i.e., symmetric confining potential) and an application to integral inequalities.
format Preprint
id arxiv_https___arxiv_org_abs_2410_04647
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Nonnegative extensions of Sturm-Liouville operators with an application to problems with symmetric coefficient functions
Fischbacher, Christoph
Stanfill, Jonathan
Spectral Theory
Primary: 34B20, 34B24, 34L05, Secondary: 47A10, 47E05
The purpose of this paper is to study nonnegative self-adjoint extensions associated with singular Sturm-Liouville expressions with strictly positive minimal operators. We provide a full characterization of all possible nonnegative self-adjoint extensions of the minimal operator in terms of generalized boundary values, as well as a parameterization of all nonnegative extensions when fixing a boundary condition at one endpoint. In addition, we investigate problems where the coefficient functions are symmetric about the midpoint of a finite interval, illustrating how every self-adjoint operator of this form is unitarily equivalent to the direct sum of two self-adjoint operators restricted to half of the interval. We also extend these result to symmetric two interval problems. We then apply our previous results to parameterize all nonnegative extensions of operators with symmetric coefficient functions. We end with an example of an operator with a symmetric Bessel-type potential (i.e., symmetric confining potential) and an application to integral inequalities.
title Nonnegative extensions of Sturm-Liouville operators with an application to problems with symmetric coefficient functions
topic Spectral Theory
Primary: 34B20, 34B24, 34L05, Secondary: 47A10, 47E05
url https://arxiv.org/abs/2410.04647