Positive definite singular kernels on two-point homogeneous spaces

Fuente: arXiv
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Main Authors: Bilyk, Dmitriy, Grabner, Peter
Format: Preprint
Published: 2024
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author Bilyk, Dmitriy
Grabner, Peter
author_facet Bilyk, Dmitriy
Grabner, Peter
contents We study positive definiteness of kernels $K(x,y)$ on two-point homogeneous spaces. As opposed to the classical case, which has been developed and studied in the existing literature, we allow the kernel to have an (integrable) singularity for $x=y$. Specifically, the Riesz kernel $d(x,y)^{-s}$ (where $d$ denotes some distance on the space) is a prominent example. We derive results analogous to Schoenberg's characterization of positive definite functions on the sphere, Schur's lemma on the positive definiteness of the product of positive definite functions, and Schoenberg's characterization of functions positive definite on all spheres. We use these results to better understand the behavior of the Riesz kernels for the geodesic and chordal distances on projective spaces.
format Preprint
id arxiv_https___arxiv_org_abs_2410_22104
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Positive definite singular kernels on two-point homogeneous spaces
Bilyk, Dmitriy
Grabner, Peter
Classical Analysis and ODEs
We study positive definiteness of kernels $K(x,y)$ on two-point homogeneous spaces. As opposed to the classical case, which has been developed and studied in the existing literature, we allow the kernel to have an (integrable) singularity for $x=y$. Specifically, the Riesz kernel $d(x,y)^{-s}$ (where $d$ denotes some distance on the space) is a prominent example. We derive results analogous to Schoenberg's characterization of positive definite functions on the sphere, Schur's lemma on the positive definiteness of the product of positive definite functions, and Schoenberg's characterization of functions positive definite on all spheres. We use these results to better understand the behavior of the Riesz kernels for the geodesic and chordal distances on projective spaces.
title Positive definite singular kernels on two-point homogeneous spaces
topic Classical Analysis and ODEs
url https://arxiv.org/abs/2410.22104