How Does Machine Learning Manage Complexity?

arXiv cs.LG / 4/9/2026

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Key Points

  • The paper proposes a computational-complexity framework for understanding why machine learning models can effectively represent and learn complex systems.
  • It argues that by targeting computable probability distributions (a subset of the broader range often found in real data), ML can manage complexity more systematically using probabilistic structure.
  • The authors model ML learning abstractly as producing P/poly-computable distributions with polynomially bounded max-entropy, rather than focusing on specific training mechanisms.
  • They show an illustrative result: if a learned model’s output distribution has low prediction error versus a distribution generated by a cryptographic pseudorandom generator, then the learned distribution must be close to uniform.

Abstract

We provide a computational complexity lens to understand the power of machine learning models, particularly their ability to model complex systems. Machine learning models are often trained on data drawn from sampleable or more complex distributions, a far wider range of distributions than just computable ones. By focusing on computable distributions, machine learning models can better manage complexity via probability. We abstract away from specific learning mechanisms, modeling machine learning as producing P/poly-computable distributions with polynomially-bounded max-entropy. We illustrate how learning computable distributions models complexity by showing that if a machine learning model produces a distribution \mu that minimizes error against the distribution generated by a cryptographic pseudorandom generator, then \mu must be close to uniform.

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