On Rayleigh-Type Formulas for a Non-local Boundary Value Problem Associated with an Integral Operator Commuting with the Laplacian

TL;DR

This paper establishes the existence and uniqueness of a negative eigenvalue for a class of integral operators with harmonic kernels, and introduces recursive formulas to approximate these eigenvalues, linking non-local boundary conditions with Laplacian eigenproblems.

Contribution

It provides new recursive methods for approximating eigenvalues of integral operators with specific kernels, connecting non-local boundary problems with classical Laplacian eigenvalues.

Findings

Proved existence and simplicity of a negative eigenvalue.

Developed recursive formulas for Rayleigh functions when ho=1.

Linked non-local boundary conditions with Laplacian eigenvalues.

Abstract

In this article we prove the existence, uniqueness, and simplicity of a negative eigenvalue for a class of integral operators whose kernel is of the form $|x-y|^\rho$, $0 < \rho \leq 1$, $x, y \in [-a, a]$. We also provide two different ways of producing recursive formulas for the Rayleigh functions (i.e., recursion formulas for power sums) of the eigenvalues of this integral operator when $\rho=1$, providing means of approximating this negative eigenvalue. These methods offer recursive procedures for dealing with the eigenvalues of a one-dimensional Laplacian with non-local boundary conditions which commutes with an integral operator having a harmonic kernel. The problem emerged in recent work by one of the authors [45]. We also discuss extensions in higher dimensions and links with distance matrices.