High-probability guarantees for linear accessibility in feature superposition

arXiv:2609.09556 · stat.ML, cs.AI, cs.IR, cs.LG, math.PR · Submitted 2026-09-09 · Read on arXiv

stat.ML, cs.AI, cs.IR, cs.LG, math.PR

Submitted: 2026-09-09

Updated: 2026-09-25

Comments: preprint

License: http://creativecommons.org/licenses/by/4.0/

The gist: Neural networks can leverage feature superposition to encode more concepts than dimensions, but cross-feature interference constrains the linear accessibility of simultaneously active features.

Terminology

Abstract

Neural networks can leverage feature superposition to encode more concepts than dimensions, but cross-feature interference constrains the linear accessibility of simultaneously active features. By framing linear accessibility as a compressed sensing problem, we derive high-probability bounds for fixed supports under subgaussian noise, proving the sufficient dimension scales linearly (d=O epsilon(k m)) rather than prior worst-case quadratic limits. We then validate these bounds across system parameters through Gaussian-tail approximations. These results quantify the geometric constraints of the linear representation hypothesis, providing a framework for evaluating sparse autoencoders, compositional generalization, and neural interpretability.

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