Sharp description of local minima in the loss landscape of high-dimensional two-layer ReLU neural networks

Fuente: arXiv
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Autori principali: Huang, Jie, Loureiro, Bruno, Mannelli, Stefano Sarao
Natura: Preprint
Pubblicazione: 2026
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author Huang, Jie
Loureiro, Bruno
Mannelli, Stefano Sarao
author_facet Huang, Jie
Loureiro, Bruno
Mannelli, Stefano Sarao
contents We study the population loss landscape of two-layer ReLU networks of the form $\sum_{k=1}^K \mathrm{ReLU}(w_k^\top x)$ in a realisable teacher-student setting with Gaussian covariates. We show that local minima admit an exact low-dimensional representation in terms of summary statistics, yielding a sharp and interpretable characterisation of the landscape. We further establish a direct link with one-pass SGD: local minima correspond to attractive fixed points of the dynamics in summary statistics space. This perspective reveals a hierarchical organisation of minima into discrete families and shows how overparameterisation changes their stability and reachability under gradient-based dynamics. In this overparameterised regime, global minima become increasingly accessible, attracting the dynamics and reducing convergence to spurious solutions. Overall, our results reveal intrinsic limitations of common simplifying assumptions, which may miss essential features of the loss landscape even in minimal neural network models.
format Preprint
id arxiv_https___arxiv_org_abs_2604_09412
institution arXiv
publishDate 2026
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spellingShingle Sharp description of local minima in the loss landscape of high-dimensional two-layer ReLU neural networks
Huang, Jie
Loureiro, Bruno
Mannelli, Stefano Sarao
Machine Learning
Disordered Systems and Neural Networks
We study the population loss landscape of two-layer ReLU networks of the form $\sum_{k=1}^K \mathrm{ReLU}(w_k^\top x)$ in a realisable teacher-student setting with Gaussian covariates. We show that local minima admit an exact low-dimensional representation in terms of summary statistics, yielding a sharp and interpretable characterisation of the landscape. We further establish a direct link with one-pass SGD: local minima correspond to attractive fixed points of the dynamics in summary statistics space. This perspective reveals a hierarchical organisation of minima into discrete families and shows how overparameterisation changes their stability and reachability under gradient-based dynamics. In this overparameterised regime, global minima become increasingly accessible, attracting the dynamics and reducing convergence to spurious solutions. Overall, our results reveal intrinsic limitations of common simplifying assumptions, which may miss essential features of the loss landscape even in minimal neural network models.
title Sharp description of local minima in the loss landscape of high-dimensional two-layer ReLU neural networks
topic Machine Learning
Disordered Systems and Neural Networks
url https://arxiv.org/abs/2604.09412