arXiv Machine Learning

Robust Learning of Multi-Index Models under Logconcave Distributions via Weak Partial Learners

The paper introduces a new algorithmic framework for learning Boolean concept classes under logconcave distributions, focusing on multi‑index models. It leverages a boosting approach based on weak partial learners, overcoming the need for distribution‑free weak learners by using a recursive moment‑based partitioning procedure that aligns low‑degree moments of conditioned distributions with the original logconcave distribution. This yields faster robust learners for fundamental concept classes such as functions of halfspaces and multiclass linear classifiers, and includes an efficient method for detecting moment discrepancies that may be useful beyond this work.

arXiv Machine Learning
Sep 17

Efficient Robust Learning at the Information-Theoretic Limit

The paper presents a polynomial‑time algorithm for robustly learning Boolean concept classes with respect to a fixed distribution, achieving the optimal error rate of η + ε where η is the noise rate. It builds on Blanc’s earlier, computationally inefficient algorithm and introduces no‑regret learners to overcome the previous limitations. Additionally, the authors provide an efficient method that does not require an ERM oracle for any function class admitting sandwiching polynomials under hypercontractive distributions, including a first polynomial‑time solution for learning halfspaces with Gaussian marginals at error η + ε.

By Adam R. Klivans, Konstantinos Stavropoulos, Sergei Tikhonov, Arsen Vasilyan
arXiv Machine Learning
Sep 3

Smoothed Analysis for Learning Concepts with Low Intrinsic Dimension

arXiv:2407. 00966v3 Announce Type: replace Abstract: In traditional models of supervised learning, the goal of a learner-- given examples from an arbitrary joint distribution on $\mathbb{R}^d \times \{\pm 1\}$-- is to output a hypothesis that is competitive (to within $\epsilon$) of the best fitting concept from some class.

By Gautam Chandrasekaran, Adam Klivans, Vasilis Kontonis, Raghu Meka, Konstantinos Stavropoulos
arXiv Machine Learning
Sep 3

Achieving More with Less: A Tensor-Optimization-Powered Ensemble Method

The paper proposes a tensor‑optimization‑powered ensemble method that uses confidence tensors to capture how each weak base classifier performs across different classes. By integrating these tensors and a smooth, partially convex objective that emphasizes margin, the method improves both classification accuracy and generalization while requiring fewer base learners. The authors also prove a property of the loss gradient that enables efficient gradient‑based optimization of the constrained problem.

By Jinghui Yuan, Weijin Jiang, Zhe Cao, Fangyuan Xie, Rong Wang, Feiping Nie, Yuan Yuan
arXiv Statistics ML
Oct 21

Optimal aggregation in multiclass classification

arXiv:2610.28025v1 Announce Type: cross Abstract: This paper studies the problem of aggregation in multiclass classification, generalizing existing results for binary classification. Given a finite d...

By Felix Abramovich, Or Davidovitch-Servadio
arXiv Machine Learning
Jul 8

Boosting with List-Decodable Codes

arXiv:2607. 05791v1 Announce Type: cross Abstract: Boosting is a fundamental technique for generically improving the accuracy of learning algorithms (Schapire 1989).

By Addison Prairie, Li-Yang Tan
arXiv Machine Learning
Jul 20

Testing Distributions Against Bounded Distinguishers

arXiv:2607. 15645v1 Announce Type: cross Abstract: Motivated by the challenge of testing distributions over high-dimensional or continuous domains, we study distribution testing with respect to bounded classes of distinguishers.

By Mark Bun, Rathin Desai, Renato Ferreira Pinto Jr