Divergence-free Linearized Neural Networks: Integral Representation and Optimal Approximation Rates

Fuente: arXiv
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Autori principali: He, Juncai, Liu, Xinliang, Tian, Zitong
Natura: Preprint
Pubblicazione: 2026
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author He, Juncai
Liu, Xinliang
Tian, Zitong
author_facet He, Juncai
Liu, Xinliang
Tian, Zitong
contents This paper studies the numerical approximation of divergence-free vector fields by linearized shallow neural networks, also referred to as random feature models or finite neuron spaces. Combining the stable potential lifting for divergence-free fields with the scalar Sobolev integral representation theory via ReLU$^k$ networks, we derive a core integral representation of divergence-free Sobolev vector fields through antisymmetric potentials parameterized by linearized ReLU$^k$ neural networks. This representation, together with a quasi-uniform distribution argument for the inner parameters, yields optimal approximation rates for such linearized ReLU$^k$ neural networks under an exact divergence-free constraint. Numerical experiments in two and three spatial dimensions, including $L^2$ projection and steady Stokes problems, confirm the theoretical rates and illustrate the effectiveness of exactly divergence-free conditions in computation.
format Preprint
id arxiv_https___arxiv_org_abs_2603_28638
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Divergence-free Linearized Neural Networks: Integral Representation and Optimal Approximation Rates
He, Juncai
Liu, Xinliang
Tian, Zitong
Numerical Analysis
41A25
G.1.2; I.2.6
This paper studies the numerical approximation of divergence-free vector fields by linearized shallow neural networks, also referred to as random feature models or finite neuron spaces. Combining the stable potential lifting for divergence-free fields with the scalar Sobolev integral representation theory via ReLU$^k$ networks, we derive a core integral representation of divergence-free Sobolev vector fields through antisymmetric potentials parameterized by linearized ReLU$^k$ neural networks. This representation, together with a quasi-uniform distribution argument for the inner parameters, yields optimal approximation rates for such linearized ReLU$^k$ neural networks under an exact divergence-free constraint. Numerical experiments in two and three spatial dimensions, including $L^2$ projection and steady Stokes problems, confirm the theoretical rates and illustrate the effectiveness of exactly divergence-free conditions in computation.
title Divergence-free Linearized Neural Networks: Integral Representation and Optimal Approximation Rates
topic Numerical Analysis
41A25
G.1.2; I.2.6
url https://arxiv.org/abs/2603.28638