Unsolved

State evolution for gradient descent beyond the mean-field scaling

Sourced from the work of Qiyang Han, Xiaocong Xu

§ Problem Statement

Setup

Consider high-dimensional empirical-risk minimization solved by gradient descent in random-design settings where the aspect ratio is allowed to deviate from the proportional mean-field regime. Existing non-asymptotic joint state-evolution guarantees in this line of work are proved under proportional scaling assumptions used in the source, together with its structured response-model conditions.

This setup follows Han & Xu (2025).

Unsolved Problem

Extend a comparable joint state-evolution theorem, with explicit finite-sample error control and time-uniform guarantees up to horizon TT, to non-mean-field regimes such as n/pn/p\to\infty and n/p0n/p\to 0, and identify the corresponding Onsager correction operators/matrices under clearly stated assumptions for those regimes.

§ Discussion

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§ Significance & Implications

Interpreting the source discussion as motivation, this problem asks whether the Onsager-corrected dependency structure developed in the mean-field analysis persists, changes form, or breaks down outside that regime, which would help relate the paper's high-dimensional theory to more classical or extreme aspect-ratio limits.

§ Known Partial Results

  • Han et al. (2025): The paper proves a non-asymptotic joint state-evolution theorem with two Onsager correction matrices in its mean-field proportional regime under its specified modeling assumptions. This entry is treated as open beyond the scope established in the cited source.

§ References

[1]

Gradient descent inference in empirical risk minimization

Qiyang Han, Xiaocong Xu (2025)

Annals of Statistics

📍 Section 2.1 (Assumption A1: proportional/mean-field regime of main interest), and Section 2.3 discussion after Theorem 2.3 around Eqs. (2.14)-(2.15), where behavior beyond mean-field/approximate low-dimensional regimes is flagged as different and not covered by the proved theorem.

Primary source; 2025 online publication in Annals of Statistics (preprint available as arXiv:2412.09498).

§ Tags