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
- arXiv Links
- Abstract ↗PDF ↗
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.