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Main Authors: Pushkin, Denys, Berthier, Raphaël, Abbe, Emmanuel
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2406.06354
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author Pushkin, Denys
Berthier, Raphaël
Abbe, Emmanuel
author_facet Pushkin, Denys
Berthier, Raphaël
Abbe, Emmanuel
contents We investigate the out-of-domain generalization of random feature (RF) models and Transformers. We first prove that in the `generalization on the unseen (GOTU)' setting, where training data is fully seen in some part of the domain but testing is made on another part, and for RF models in the small feature regime, the convergence takes place to interpolators of minimal degree as in the Boolean case (Abbe et al., 2023). We then consider the sparse target regime and explain how this regime relates to the small feature regime, but with a different regularization term that can alter the picture in the non-Boolean case. We show two different outcomes for the sparse regime with q-ary data tokens: (1) if the data is embedded with roots of unities, then a min-degree interpolator is learned like in the Boolean case for RF models, (2) if the data is not embedded as such, e.g., simply as integers, then RF models and Transformers may not learn minimal degree interpolators. This shows that the Boolean setting and its roots of unities generalization are special cases where the minimal degree interpolator offers a rare characterization of how learning takes place. For more general integer and real-valued settings, a more nuanced picture remains to be fully characterized.
format Preprint
id arxiv_https___arxiv_org_abs_2406_06354
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publishDate 2024
record_format arxiv
spellingShingle On the Minimal Degree Bias in Generalization on the Unseen for non-Boolean Functions
Pushkin, Denys
Berthier, Raphaël
Abbe, Emmanuel
Machine Learning
We investigate the out-of-domain generalization of random feature (RF) models and Transformers. We first prove that in the `generalization on the unseen (GOTU)' setting, where training data is fully seen in some part of the domain but testing is made on another part, and for RF models in the small feature regime, the convergence takes place to interpolators of minimal degree as in the Boolean case (Abbe et al., 2023). We then consider the sparse target regime and explain how this regime relates to the small feature regime, but with a different regularization term that can alter the picture in the non-Boolean case. We show two different outcomes for the sparse regime with q-ary data tokens: (1) if the data is embedded with roots of unities, then a min-degree interpolator is learned like in the Boolean case for RF models, (2) if the data is not embedded as such, e.g., simply as integers, then RF models and Transformers may not learn minimal degree interpolators. This shows that the Boolean setting and its roots of unities generalization are special cases where the minimal degree interpolator offers a rare characterization of how learning takes place. For more general integer and real-valued settings, a more nuanced picture remains to be fully characterized.
title On the Minimal Degree Bias in Generalization on the Unseen for non-Boolean Functions
topic Machine Learning
url https://arxiv.org/abs/2406.06354