Optimal Non-Asymptotic Edgeworth Expansions for Multivariate Neural Network Outputs

Fuente: arXiv
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Main Author: Celli, Lucia
Format: Preprint
Published: 2026
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author Celli, Lucia
author_facet Celli, Lucia
contents Finite-width fully connected neural networks with Gaussian-initialized weights deviate from their infinite-width Gaussian limit, exhibiting non-vanishing higher-order cumulants. We approximate these deviations, for a neural network evaluated in a finite number of inputs, using multidimensional Edgeworth expansions of arbitrary order $4m-1$, with $m\in\mathbb{N}$. Assuming that the corresponding Gaussian limit has an invertible covariance matrix and that the activation function is polynomially bounded, we establish a bound of order $n^{-m}$ on the total variation distance between the law of the true network output and its Edgeworth approximation, with matching lower bounds. As an application, we quantify the error in Bayesian posterior distributions when the prior is replaced by its Edgeworth expansion. Our results are more general and also apply to sequences of conditionally Gaussian vectors converging to a Gaussian vector with invertible covariance.
format Preprint
id arxiv_https___arxiv_org_abs_2605_24072
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Optimal Non-Asymptotic Edgeworth Expansions for Multivariate Neural Network Outputs
Celli, Lucia
Machine Learning
Probability
60E10 (Primary) 60F05, 60G15, 60G60, 68T07, 62C10 (Secondary)
G.3; I.2
Finite-width fully connected neural networks with Gaussian-initialized weights deviate from their infinite-width Gaussian limit, exhibiting non-vanishing higher-order cumulants. We approximate these deviations, for a neural network evaluated in a finite number of inputs, using multidimensional Edgeworth expansions of arbitrary order $4m-1$, with $m\in\mathbb{N}$. Assuming that the corresponding Gaussian limit has an invertible covariance matrix and that the activation function is polynomially bounded, we establish a bound of order $n^{-m}$ on the total variation distance between the law of the true network output and its Edgeworth approximation, with matching lower bounds. As an application, we quantify the error in Bayesian posterior distributions when the prior is replaced by its Edgeworth expansion. Our results are more general and also apply to sequences of conditionally Gaussian vectors converging to a Gaussian vector with invertible covariance.
title Optimal Non-Asymptotic Edgeworth Expansions for Multivariate Neural Network Outputs
topic Machine Learning
Probability
60E10 (Primary) 60F05, 60G15, 60G60, 68T07, 62C10 (Secondary)
G.3; I.2
url https://arxiv.org/abs/2605.24072