arXiv Machine Learning By Ilias Diakonikolas, Daniel M. Kane, Mingchen Ma

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

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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.

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