arXiv Machine Learning

Shortcomings and capacities of real-constrained neural networks in complex spaces

arXiv:2606. 04390v1 Announce Type: new Abstract: We find the asymptotic ratio between the storage capacities when enforcing real pre-activations in a complex hypothesis class as opposed to complex ones in the same class.

arXiv Machine Learning
Jul 14

Approximation of Analytic Functions by ReLU Neural Networks with Adjustable Depth and Width

arXiv:2607. 10589v1 Announce Type: cross Abstract: In contrast to most studies on neural network approximation theory that characterize results through a single parameter, such as the total number of network parameters, \cite{shen2020deep} pioneered the characterization of approximation rates as a joint function of the width parameter $N$ and the depth parameter $L$, thereby granting greater architectural flexibility.

By Yanming Lai, Defeng Sun, Yang Wang
arXiv Machine Learning
Oct 22

Depth Separation for Neural Networks under Gaussian Measure

The paper investigates depth separation for neural networks in the context of $L^2$ approximation of radial functions under a standard Gaussian measure in $d$ dimensions. It demonstrates that a particular radial function can be approximated within a fixed small $L^2$ error by a depth‑3 ReLU network of polynomial size in $d$, yet any depth‑2 network approximating the same function with bounded weights must have size exponential in $d$. The authors prove a general result linking high‑frequency Hermite expansion mass to the limitations of depth‑2 networks with small width and bounded weights, and all results are formally verified in Lean 4.

By Cynthia Bortolotto, Francisco Ganacim, Roberto I. Oliveira