The Sample Complexity of Smooth Boosting and the Tightness of the Hardcore Theorem

Fuente: arXiv
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Main Authors: Blanc, Guy, Hayderi, Alexandre, Koch, Caleb, Tan, Li-Yang
Format: Preprint
Published: 2024
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author Blanc, Guy
Hayderi, Alexandre
Koch, Caleb
Tan, Li-Yang
author_facet Blanc, Guy
Hayderi, Alexandre
Koch, Caleb
Tan, Li-Yang
contents Smooth boosters generate distributions that do not place too much weight on any given example. Originally introduced for their noise-tolerant properties, such boosters have also found applications in differential privacy, reproducibility, and quantum learning theory. We study and settle the sample complexity of smooth boosting: we exhibit a class that can be weak learned to $γ$-advantage over smooth distributions with $m$ samples, for which strong learning over the uniform distribution requires $\tildeΩ(1/γ^2)\cdot m$ samples. This matches the overhead of existing smooth boosters and provides the first separation from the setting of distribution-independent boosting, for which the corresponding overhead is $O(1/γ)$. Our work also sheds new light on Impagliazzo's hardcore theorem from complexity theory, all known proofs of which can be cast in the framework of smooth boosting. For a function $f$ that is mildly hard against size-$s$ circuits, the hardcore theorem provides a set of inputs on which $f$ is extremely hard against size-$s'$ circuits. A downside of this important result is the loss in circuit size, i.e. that $s' \ll s$. Answering a question of Trevisan, we show that this size loss is necessary and in fact, the parameters achieved by known proofs are the best possible.
format Preprint
id arxiv_https___arxiv_org_abs_2409_11597
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The Sample Complexity of Smooth Boosting and the Tightness of the Hardcore Theorem
Blanc, Guy
Hayderi, Alexandre
Koch, Caleb
Tan, Li-Yang
Computational Complexity
Data Structures and Algorithms
Machine Learning
Smooth boosters generate distributions that do not place too much weight on any given example. Originally introduced for their noise-tolerant properties, such boosters have also found applications in differential privacy, reproducibility, and quantum learning theory. We study and settle the sample complexity of smooth boosting: we exhibit a class that can be weak learned to $γ$-advantage over smooth distributions with $m$ samples, for which strong learning over the uniform distribution requires $\tildeΩ(1/γ^2)\cdot m$ samples. This matches the overhead of existing smooth boosters and provides the first separation from the setting of distribution-independent boosting, for which the corresponding overhead is $O(1/γ)$. Our work also sheds new light on Impagliazzo's hardcore theorem from complexity theory, all known proofs of which can be cast in the framework of smooth boosting. For a function $f$ that is mildly hard against size-$s$ circuits, the hardcore theorem provides a set of inputs on which $f$ is extremely hard against size-$s'$ circuits. A downside of this important result is the loss in circuit size, i.e. that $s' \ll s$. Answering a question of Trevisan, we show that this size loss is necessary and in fact, the parameters achieved by known proofs are the best possible.
title The Sample Complexity of Smooth Boosting and the Tightness of the Hardcore Theorem
topic Computational Complexity
Data Structures and Algorithms
Machine Learning
url https://arxiv.org/abs/2409.11597