Deep Neural Network Approximation of Composition Functions: with application to PINNs
Abstract
In this paper, we focus on approximating a natural class of functions that are compositions of smooth functions. Unlike the low-dimensional support assumption on the covariate, we demonstrate that composition functions have an intrinsic sparse structure if we assume each layer in the composition has a small degree of freedom. This fact can alleviate the curse of dimensionality in approximation errors by neural networks. Specifically, by using mathematical induction and the multivariate Faa di Bruno formula, we extend the approximation theory of deep neural networks to the composition functions case. Furthermore, combining recent results on the statistical error of deep learning, we provide a general convergence rate analysis for the PINNs method in solving elliptic equations with compositional solutions. We also present two simple illustrative numerical examples to demonstrate the effect of the intrinsic sparse structure in regression and solving PDEs.
Cite
@article{arxiv.2304.07947,
title = {Deep Neural Network Approximation of Composition Functions: with application to PINNs},
author = {Chenguang Duan and Yuling Jiao and Xiliang Lu and Jerry Zhijian Yang and Cheng Yuan},
journal= {arXiv preprint arXiv:2304.07947},
year = {2023}
}
Comments
There are errors in the crucial Lemma 3.1, which is a result from our previous work that has not undergone peer review. During the refinement of this manuscript, one of our colleagues pointed out a potential mistake in the proof of this result, indicating that certain corrections are needed to ensure its correctness. To uphold academic rigor, we decide to withdraw the paper at this time