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arXiv · 2608.11346

Distribution-Free Halfspace Testing with Samples

Xi Chen·Renato Ferreira Pinto Jr.·Nathaniel Harms·Shyamal Patel·Rocco A. Servedio
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Abstract

We prove a tight $\Theta(n/\epsilon)$ lower bound on the number of samples required for testing halfspaces over $\mathbb{R}^n$, in the distribution-free sample-based model where the underlying probability distribution is unknown to the algorithm, and the algorithm only receives random samples (i.e., it cannot make queries). This shows that testing is no more efficient than learning for halfspaces. We also show a matching upper bound for one-sided testers, improving on the standard (two-sided) testing-by-learning reduction, establishing that two-sided halfspace testers in this model have no advantage over one-sided testers.

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Xi Chen, Renato Ferreira Pinto Jr., Nathaniel Harms, Shyamal Patel, Rocco A. Servedio. 2026-08-11. Distribution-Free Halfspace Testing with Samples. https://arxiv.org/abs/2608.11346

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