Vector-Valued Gaussian Processes and their Kernels on a Class of Metric Graphs

Fuente: arXiv
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Hauptverfasser: Filosi, Tobia, Porcu, Emilio, Emery, Xavier, Agostinelli, Claudio, Alegrìa, Alfredo
Format: Preprint
Veröffentlicht: 2025
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author Filosi, Tobia
Porcu, Emilio
Emery, Xavier
Agostinelli, Claudio
Alegrìa, Alfredo
author_facet Filosi, Tobia
Porcu, Emilio
Emery, Xavier
Agostinelli, Claudio
Alegrìa, Alfredo
contents Despite the increasing importance of stochastic processes on linear networks and graphs, current literature on multivariate (vector-valued) Gaussian random fields on metric graphs is elusive. This paper challenges several aspects related to the construction of proper matrix-valued kernels structures. We start by considering matrix-valued metrics that can be composed with scalar- or matrix-valued functions to implement valid kernels associated with vector-valued Gaussian fields. We then provide conditions for certain classes of matrix-valued functions to be composed with the univariate resistance metric and ensure positive semidefiniteness. Special attention is then devoted to Euclidean trees, where a substantial effort is required given the absence of literature related to multivariate kernels depending on the $\ell_1$ metric. Hence, we provide a foundational contribution to certain classes of matrix-valued positive semidefinite functions depending on the $\ell_1$ metric. This fact is then used to characterise kernels on Euclidean trees with a finite number of leaves. Amongst those, we provide classes of matrix-valued covariance functions that are compactly supported.
format Preprint
id arxiv_https___arxiv_org_abs_2501_10208
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Vector-Valued Gaussian Processes and their Kernels on a Class of Metric Graphs
Filosi, Tobia
Porcu, Emilio
Emery, Xavier
Agostinelli, Claudio
Alegrìa, Alfredo
Statistics Theory
Despite the increasing importance of stochastic processes on linear networks and graphs, current literature on multivariate (vector-valued) Gaussian random fields on metric graphs is elusive. This paper challenges several aspects related to the construction of proper matrix-valued kernels structures. We start by considering matrix-valued metrics that can be composed with scalar- or matrix-valued functions to implement valid kernels associated with vector-valued Gaussian fields. We then provide conditions for certain classes of matrix-valued functions to be composed with the univariate resistance metric and ensure positive semidefiniteness. Special attention is then devoted to Euclidean trees, where a substantial effort is required given the absence of literature related to multivariate kernels depending on the $\ell_1$ metric. Hence, we provide a foundational contribution to certain classes of matrix-valued positive semidefinite functions depending on the $\ell_1$ metric. This fact is then used to characterise kernels on Euclidean trees with a finite number of leaves. Amongst those, we provide classes of matrix-valued covariance functions that are compactly supported.
title Vector-Valued Gaussian Processes and their Kernels on a Class of Metric Graphs
topic Statistics Theory
url https://arxiv.org/abs/2501.10208