The Power of Iterative Filtering for Supervised Learning with (Heavy) Contamination

Fuente: arXiv
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Auteurs principaux: Klivans, Adam R., Stavropoulos, Konstantinos, Tian, Kevin, Vasilyan, Arsen
Format: Preprint
Publié: 2025
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author Klivans, Adam R.
Stavropoulos, Konstantinos
Tian, Kevin
Vasilyan, Arsen
author_facet Klivans, Adam R.
Stavropoulos, Konstantinos
Tian, Kevin
Vasilyan, Arsen
contents Inspired by recent work on learning with distribution shift, we give a general outlier removal algorithm called iterative polynomial filtering and show a number of striking applications for supervised learning with contamination: (1) We show that any function class that can be approximated by low-degree polynomials with respect to a hypercontractive distribution can be efficiently learned under bounded contamination (also known as nasty noise). This is a surprising resolution to a longstanding gap between the complexity of agnostic learning and learning with contamination, as it was widely believed that low-degree approximators only implied tolerance to label noise. In particular, it implies the first efficient algorithm for learning halfspaces with $η$-bounded contamination up to error $2η+ε$ with respect to the Gaussian distribution. (2) For any function class that admits the (stronger) notion of sandwiching approximators, we obtain near-optimal learning guarantees even with respect to heavy additive contamination, where far more than $1/2$ of the training set may be added adversarially. Prior related work held only for regression and in a list-decodable setting. (3) We obtain the first efficient algorithms for tolerant testable learning of functions of halfspaces with respect to any fixed log-concave distribution. Even the non-tolerant case for a single halfspace in this setting had remained open. These results significantly advance our understanding of efficient supervised learning under contamination, a setting that has been much less studied than its unsupervised counterpart.
format Preprint
id arxiv_https___arxiv_org_abs_2505_20177
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle The Power of Iterative Filtering for Supervised Learning with (Heavy) Contamination
Klivans, Adam R.
Stavropoulos, Konstantinos
Tian, Kevin
Vasilyan, Arsen
Machine Learning
Data Structures and Algorithms
Inspired by recent work on learning with distribution shift, we give a general outlier removal algorithm called iterative polynomial filtering and show a number of striking applications for supervised learning with contamination: (1) We show that any function class that can be approximated by low-degree polynomials with respect to a hypercontractive distribution can be efficiently learned under bounded contamination (also known as nasty noise). This is a surprising resolution to a longstanding gap between the complexity of agnostic learning and learning with contamination, as it was widely believed that low-degree approximators only implied tolerance to label noise. In particular, it implies the first efficient algorithm for learning halfspaces with $η$-bounded contamination up to error $2η+ε$ with respect to the Gaussian distribution. (2) For any function class that admits the (stronger) notion of sandwiching approximators, we obtain near-optimal learning guarantees even with respect to heavy additive contamination, where far more than $1/2$ of the training set may be added adversarially. Prior related work held only for regression and in a list-decodable setting. (3) We obtain the first efficient algorithms for tolerant testable learning of functions of halfspaces with respect to any fixed log-concave distribution. Even the non-tolerant case for a single halfspace in this setting had remained open. These results significantly advance our understanding of efficient supervised learning under contamination, a setting that has been much less studied than its unsupervised counterpart.
title The Power of Iterative Filtering for Supervised Learning with (Heavy) Contamination
topic Machine Learning
Data Structures and Algorithms
url https://arxiv.org/abs/2505.20177