Posterior Bayesian Neural Networks with Dependent Weights

Fuente: arXiv
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Autores principales: Apollonio, Nicola, Franzina, Giovanni, Torrisi, Giovanni Luca
Formato: Preprint
Publicado: 2025
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author Apollonio, Nicola
Franzina, Giovanni
Torrisi, Giovanni Luca
author_facet Apollonio, Nicola
Franzina, Giovanni
Torrisi, Giovanni Luca
contents We consider fully connected and feedforward deep neural networks with dependent and possibly heavy-tailed weights, as introduced in [26], to address limitations of the standard Gaussian prior. It has been proved in [26] that, as the number of nodes in the hidden layers grows large, according to a sequential and ordered limit, the law of the output converges weakly to a Gaussian mixture. In this paper, we study the neural network through the lens of the posterior distribution with a Gaussian likelihood. If the random covariance matrix of the infinite-width limit is positive definite under the prior, we identify the posterior distribution of the output in the wide-width limit according to a sequential regime. Remarkably, we provide mild sufficient conditions to ensure the aforementioned invertibility of the random covariance matrix under the prior, thereby extending the results in [8]. Among our results, we present sufficient conditions on some model parameters (the activation function and the associated Lévy measures) which ensure that the sequential limits are independent of the order. We illustrate our findings with examples and numerical simulations.
format Preprint
id arxiv_https___arxiv_org_abs_2507_22095
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Posterior Bayesian Neural Networks with Dependent Weights
Apollonio, Nicola
Franzina, Giovanni
Torrisi, Giovanni Luca
Machine Learning
Probability
60F05, 62F15, 68T07
We consider fully connected and feedforward deep neural networks with dependent and possibly heavy-tailed weights, as introduced in [26], to address limitations of the standard Gaussian prior. It has been proved in [26] that, as the number of nodes in the hidden layers grows large, according to a sequential and ordered limit, the law of the output converges weakly to a Gaussian mixture. In this paper, we study the neural network through the lens of the posterior distribution with a Gaussian likelihood. If the random covariance matrix of the infinite-width limit is positive definite under the prior, we identify the posterior distribution of the output in the wide-width limit according to a sequential regime. Remarkably, we provide mild sufficient conditions to ensure the aforementioned invertibility of the random covariance matrix under the prior, thereby extending the results in [8]. Among our results, we present sufficient conditions on some model parameters (the activation function and the associated Lévy measures) which ensure that the sequential limits are independent of the order. We illustrate our findings with examples and numerical simulations.
title Posterior Bayesian Neural Networks with Dependent Weights
topic Machine Learning
Probability
60F05, 62F15, 68T07
url https://arxiv.org/abs/2507.22095