ReLU CNNs in Korobov spaces lift the approximation order from second order to order m+1, with far weaker dimensional growth than the Sobolev case
This work studies the Lp error of approximating higher-order Korobov functions f∈Km+1_p(Ω) by deep ReLU convolutional neural networks (CNNs), proving that for depth L≤Csd4m3N(log_2 N) there exists a network with inf‖f−f_L‖Lp(Ω)≤Cm,d‖Dm+1f‖Lp(Ω)N−m−1(log_2 N)(m+2)(d−1), i.e. it improves the classical second-order mixed-derivative rate O(L−2+1/p) to order (m+1) up to a logarithmic factor, and concludes that the higher-order expressivity of CNNs does not severely suffer from the curse of dimensionality.