Student-t processes as infinite-width limits of posterior Bayesian neural networks

Fuente: arXiv
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Autores principales: Caporali, Francesco, Favaro, Stefano, Trevisan, Dario
Formato: Preprint
Publicado: 2025
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author Caporali, Francesco
Favaro, Stefano
Trevisan, Dario
author_facet Caporali, Francesco
Favaro, Stefano
Trevisan, Dario
contents The asymptotic properties of Bayesian Neural Networks (BNNs) have been extensively studied, particularly regarding their approximations by Gaussian processes in the infinite-width limit. We extend these results by showing that posterior BNNs can be approximated by Student-t processes, which offer greater flexibility in modeling uncertainty. Specifically, we show that, if the parameters of a BNN follow a Gaussian prior distribution, and the variance of both the last hidden layer and the Gaussian likelihood function follows an Inverse-Gamma prior distribution, then the resulting posterior BNN converges to a Student-t process in the infinite-width limit. Our proof leverages the Wasserstein metric to establish control over the convergence rate of the Student-t process approximation.
format Preprint
id arxiv_https___arxiv_org_abs_2502_04247
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Student-t processes as infinite-width limits of posterior Bayesian neural networks
Caporali, Francesco
Favaro, Stefano
Trevisan, Dario
Machine Learning
Probability
The asymptotic properties of Bayesian Neural Networks (BNNs) have been extensively studied, particularly regarding their approximations by Gaussian processes in the infinite-width limit. We extend these results by showing that posterior BNNs can be approximated by Student-t processes, which offer greater flexibility in modeling uncertainty. Specifically, we show that, if the parameters of a BNN follow a Gaussian prior distribution, and the variance of both the last hidden layer and the Gaussian likelihood function follows an Inverse-Gamma prior distribution, then the resulting posterior BNN converges to a Student-t process in the infinite-width limit. Our proof leverages the Wasserstein metric to establish control over the convergence rate of the Student-t process approximation.
title Student-t processes as infinite-width limits of posterior Bayesian neural networks
topic Machine Learning
Probability
url https://arxiv.org/abs/2502.04247