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Main Authors: Ahmadi, Saba, Yang, Kunhe, Zhang, Hanrui
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2407.11619
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author Ahmadi, Saba
Yang, Kunhe
Zhang, Hanrui
author_facet Ahmadi, Saba
Yang, Kunhe
Zhang, Hanrui
contents We study the problem of online binary classification in settings where strategic agents can modify their observable features to receive a positive classification. We model the set of feasible manipulations by a directed graph over the feature space, and assume the learner only observes the manipulated features instead of the original ones. We introduce the Strategic Littlestone Dimension, a new combinatorial measure that captures the joint complexity of the hypothesis class and the manipulation graph. We demonstrate that it characterizes the instance-optimal mistake bounds for deterministic learning algorithms in the realizable setting. We also achieve improved regret in the agnostic setting by a refined agnostic-to-realizable reduction that accounts for the additional challenge of not observing agents' original features. Finally, we relax the assumption that the learner knows the manipulation graph, instead assuming their knowledge is captured by a family of graphs. We derive regret bounds in both the realizable setting where all agents manipulate according to the same graph within the graph family, and the agnostic setting where the manipulation graphs are chosen adversarially and not consistently modeled by a single graph in the family.
format Preprint
id arxiv_https___arxiv_org_abs_2407_11619
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Strategic Littlestone Dimension: Improved Bounds on Online Strategic Classification
Ahmadi, Saba
Yang, Kunhe
Zhang, Hanrui
Machine Learning
Computer Science and Game Theory
We study the problem of online binary classification in settings where strategic agents can modify their observable features to receive a positive classification. We model the set of feasible manipulations by a directed graph over the feature space, and assume the learner only observes the manipulated features instead of the original ones. We introduce the Strategic Littlestone Dimension, a new combinatorial measure that captures the joint complexity of the hypothesis class and the manipulation graph. We demonstrate that it characterizes the instance-optimal mistake bounds for deterministic learning algorithms in the realizable setting. We also achieve improved regret in the agnostic setting by a refined agnostic-to-realizable reduction that accounts for the additional challenge of not observing agents' original features. Finally, we relax the assumption that the learner knows the manipulation graph, instead assuming their knowledge is captured by a family of graphs. We derive regret bounds in both the realizable setting where all agents manipulate according to the same graph within the graph family, and the agnostic setting where the manipulation graphs are chosen adversarially and not consistently modeled by a single graph in the family.
title Strategic Littlestone Dimension: Improved Bounds on Online Strategic Classification
topic Machine Learning
Computer Science and Game Theory
url https://arxiv.org/abs/2407.11619