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2203.12794

Learning the Dynamics of Autonomous Linear Systems From Multiple Trajectories

Lei Xin, George Chiu, Shreyas Sundaram

correctmedium confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper proves a nonasymptotic high-probability bound on the least-squares estimator Ĝ via the innovations-form regression, controlling (Y−Y−*)−1, a Gaussian cross term, and mean-dependent terms; see the exact identity, estimator, decomposition, and Theorem 1 with the same ε1, ε2, ε3 and thresholds N0, N1, N2 in the paper . The candidate solution reproduces this argument step-by-step (same regression identity, the same Gram lower bound, the same scaling for S1 via Gaussian concentration, and the same linear/quadratic-in-‖X̂0‖ terms), differing only in technique for the cross term S1 (matrix Bernstein vs the paper’s Gaussian product lemma) but yielding the same bound and constants.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper gives a careful, correct, and useful finite-sample analysis for subspace identification in a multiple-trajectory, no-input setting without steady-state assumptions. The main theorem is technically sound and practically informative, with explicit constants. Minor clarifications (e.g., role of Assumption 2 in Theorem 1) and pointers to alternative tools would improve accessibility.