Piecewise Polynomial Regression of Tame Functions via Integer Programming

12 Sept 2025 (modified: 11 Feb 2026)Submitted to ICLR 2026EveryoneRevisionsBibTeXCC BY 4.0
Keywords: tame functions, o-minimality, piecewise polynomial functions, regression
TL;DR: We approximate nonsmooth nonconvex, yet tame, functions with piecewise polynomial functions.
Abstract: Tame functions are a class of nonsmooth, nonconvex functions that appear in a wide range of applications: in training deep neural networks with all common activations, as value functions of mixed-integer programs, or as wave functions of small molecules. We consider approximating tame functions with piecewise polynomial functions. We present a theoretical bound on the approximation quality of a tame function by a piecewise polynomial function. We also present mixed-integer programming formulations of piecewise polynomial regression and demonstrate promising computational results.
Supplementary Material: zip
Primary Area: learning theory
Submission Number: 4369
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