Title
Approximating Continuous Functions by ReLU Nets of Minimal Width.
Abstract
This article concerns the expressive power of depth in deep feed-forward neural nets with ReLU activations. Specifically, we answer the following question: for a fixed $dgeq 1,$ what is the minimal width $w$ so that neural nets with ReLU activations, input dimension $d$, hidden layer widths at most $w,$ and arbitrary depth can approximate any continuous function of $d$ variables arbitrarily well. It turns out that this minimal width is exactly equal to $d+1.$ That is, if all the hidden layer widths are bounded by $d$, then even in the infinite depth limit, ReLU nets can only express a very limited class of functions. On the other hand, we show that any continuous function on the $d$-dimensional unit cube can be approximated to arbitrary precision by ReLU nets in which all hidden layers have width exactly $d+1.$ Our construction gives quantitative depth estimates for such an approximation.
Year
Venue
Field
2017
arXiv: Machine Learning
Discrete mathematics,Continuous function,Mathematical optimization,Arbitrary-precision arithmetic,Unit cube,Artificial neural network,Expressive power,Mathematics,Bounded function
DocType
Volume
Citations 
Journal
abs/1710.11278
13
PageRank 
References 
Authors
0.72
14
2
Name
Order
Citations
PageRank
Boris Hanin1474.04
Mark Sellke2142.11