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2502.03802

MXMap: A Multivariate Cross Mapping Framework for Causal Discovery in Dynamical Systems

Elise Zhang, François Mirallès, Raphaël Rousseau-Rizzi, Di Wu, Arnaud Zinflou, Benoit Boulet

incompletemedium confidence
Category
math.DS
Journal tier
Specialist/Solid
Processed
Sep 28, 2025, 12:56 AM

Audit review

The paper defines ρAll, ρDirect, and γ and uses an empirical threshold γ⋆ to prune edges in a two‑phase MXMap pipeline, but it does not claim any population‑level correctness guarantees; its justification is heuristic and empirical (Algorithm 1; Secs. 2.3, 3.2–3.3) . The candidate solution rigorously shows a degeneracy under ideal Takens/SSR assumptions: as sample size grows, CCM reconstructions become exact and multiPCM’s conditional reconstruction collapses to the target variable, making ρAll→1 and ρDirect→0 whenever the conditioning set is nonempty; thus γ→0 even when a true direct edge coexists with an indirect path, so MXMap will prune true direct edges for large T. This directly refutes any putative universal-consistency claim, which the paper does not make.

Referee report (LaTeX)

\textbf{Recommendation:} major revisions

\textbf{Journal Tier:} specialist/solid

\textbf{Justification:}

The work offers a useful multivariate extension of PCM and a pragmatic two-phase pipeline with strong empirical results. However, as currently written, the text could be misread as suggesting population-level discriminability without stating the conditions under which the γ ratio is theoretically meaningful. Clarifying that thresholds are empirical and discussing the deterministic-limit degeneracy (and how practical noise/under-embedding alleviates it) would materially improve the paper's rigor without diminishing its practical value.