English

On rates of convergence for sample average approximations without smoothness

Optimization and Control 2026-04-29 v1

Abstract

Sample average approximation (SAA) replaces an intractable expected objective by an empirical average and is a basic device of modern stochastic optimization. We develop a rate theory for optimal values and empirical ε\varepsilon-minimizers that does not assume continuity, lower semicontinuity, or smooth perturbation structure of the sample objectives. Working on (X)\ell^{\infty}(X) with the Hoffmann--J{\o}rgensen outer-probability formalism, we show that uniform control of the empirical objective process transfers deterministically to convergence rates for optimal values, excess risks of empirical ε\varepsilon-minimizers, and, under a sharp-growth condition, distances to the expected objective solution set. Combined with the directional differentiability of the infimum functional, this yields weak limits for empirical optimal values at the n1/2n^{-1/2} scale. Combined with LILs and maximal inequalities, it yields outer almost-sure and outer-mean rates. The definability, envelope, and VC-subgraph hypotheses are verified for definable discontinuous or non-Lipschitz classes arising in direct 00--11 classification, fixed-architecture neural networks, threshold regression, and non-Lipschitz p\ell_{p}-type objectives with rational 0<p<10<p<1. Practical sufficient conditions for measurability hypotheses are discussed. Together, the framework extends continuity-based SAA theory to a tame-topological setting.

Keywords

Cite

@article{arxiv.2604.25153,
  title  = {On rates of convergence for sample average approximations without smoothness},
  author = {Hien Duy Nguyen and Jacob Westerhout and Xin Guo},
  journal= {arXiv preprint arXiv:2604.25153},
  year   = {2026}
}
R2 v1 2026-07-01T12:38:23.693Z