Optimal Neural Network Approximation via Empirical Least Squares with Deterministic Samples

arXiv:2608.06687 · math.NA, cs.LG, cs.NA · Submitted 2026-08-07 · Read on arXiv

Xinliang Liu, Tong Mao, Jinchao Xu

math.NA, cs.LG, cs.NA

Submitted: 2026-08-07

Updated: 2026-08-10

License: http://creativecommons.org/licenses/by/4.0/

The gist: We develop a rigorous theory of discrete residual least-squares approximation for elliptic spectral equations L beta u=f using linearized ReLU k neural networks on the sphere, where L beta is a

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Abstract

We develop a rigorous theory of discrete residual least-squares approximation for elliptic spectral equations L beta u=f using linearized ReLU k neural networks on the sphere, where L beta is a positive elliptic spectral multiplier of order beta. Given a parameter set n= theta j* j=1 n S d, we approximate u in the linearized network space L n k(n) by the discrete residual on the collocation points eta i* i=1 m u n,m in v n in L n k(n) 1m sum i=1 m (f(eta i*)- L beta v n(eta i*)) squared. With k> d-1 over 2+ beta, for antipodally quasi-uniform network parameter sets and any quasi-uniform collocation points with m n, we prove that u-u n,m H beta(S d) f- L beta u n,m L 2(S d) n-r over d f W r,p(S d),& d over p<r at most d over 2, p>2, f H r(S d),&r> d over 2. We also establish a high-probability residual estimate, up to a logarithmic factor and an arbitrarily small smoothness loss, for i.i.d. uniformly distributed collocation points. The key analytical ingredient is a Bernstein inequality for linearized ReLU k network spaces. If h denotes the antipodal separation distance of the network parameters, then v n H r(S d) h-(r-s)v n H s(S d), 0 at most s<r<k+ 12.

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