Sample Path Regularity of Gaussian Processes from the Covariance Kernel

Fuente: arXiv
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Main Authors: Da Costa, Nathaël, Pförtner, Marvin, Da Costa, Lancelot, Hennig, Philipp
Format: Preprint
Published: 2023
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author Da Costa, Nathaël
Pförtner, Marvin
Da Costa, Lancelot
Hennig, Philipp
author_facet Da Costa, Nathaël
Pförtner, Marvin
Da Costa, Lancelot
Hennig, Philipp
contents Gaussian processes (GPs) are the most common formalism for defining probability distributions over spaces of functions. While applications of GPs are myriad, a comprehensive understanding of GP sample paths, i.e. the function spaces over which they define a probability measure, is lacking. In practice, GPs are not constructed through a probability measure, but instead through a mean function and a covariance kernel. In this paper we provide necessary and sufficient conditions on the covariance kernel for the sample paths of the corresponding GP to attain a given regularity. We focus primarily on Hölder regularity as it grants particularly straightforward conditions, which simplify further in the cases of stationary and isotropic GPs. We then demonstrate that our results allow for novel and unusually tight characterisations of the sample path regularities of the GPs commonly used in machine learning applications, such as the Matérn GPs.
format Preprint
id arxiv_https___arxiv_org_abs_2312_14886
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Sample Path Regularity of Gaussian Processes from the Covariance Kernel
Da Costa, Nathaël
Pförtner, Marvin
Da Costa, Lancelot
Hennig, Philipp
Machine Learning
Probability
Statistics Theory
Gaussian processes (GPs) are the most common formalism for defining probability distributions over spaces of functions. While applications of GPs are myriad, a comprehensive understanding of GP sample paths, i.e. the function spaces over which they define a probability measure, is lacking. In practice, GPs are not constructed through a probability measure, but instead through a mean function and a covariance kernel. In this paper we provide necessary and sufficient conditions on the covariance kernel for the sample paths of the corresponding GP to attain a given regularity. We focus primarily on Hölder regularity as it grants particularly straightforward conditions, which simplify further in the cases of stationary and isotropic GPs. We then demonstrate that our results allow for novel and unusually tight characterisations of the sample path regularities of the GPs commonly used in machine learning applications, such as the Matérn GPs.
title Sample Path Regularity of Gaussian Processes from the Covariance Kernel
topic Machine Learning
Probability
Statistics Theory
url https://arxiv.org/abs/2312.14886