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2508.13794

Learning iterated function systems from time series of partial observations

Emilia Gibson, Jeroen S.W. Lamb

incompletemedium confidence
Category
Not specified
Journal tier
Strong Field
Processed
Sep 28, 2025, 12:57 AM

Audit review

The paper correctly formalizes delay-embedded IFSs and provides a sound graph-theoretic unembedding of the time-delay embedded Markov chain (Algorithm 3.1 with Theorem 3.6), and a conditional bundle-conjugacy statement (Theorem 4.1). However, its main theorem relies on an unproven step: that one can actually construct/learn generators g_i whose delay-space evolution exactly realizes the reduced dynamics (5) from partial observations, which the paper motivates via optimization but does not establish rigorously. The candidate model goes further by attempting an explicit construction on a disjoint union of charts but (i) incorrectly infers a positive Euclidean gap δ from Whitney C^q separation and (ii) defines generators g_i that depend implicitly on future symbols, so they are not well-defined as fixed maps independent of the base sequence. Hence both are incomplete relative to the posed problem.

Referee report (LaTeX)

\textbf{Recommendation:} major revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The manuscript addresses the nontrivial problem of learning Markov-driven IFSs from partial observations by blending delay embeddings, graph-based reconstruction, and latent-variable model discovery. The unembedding algorithm and the conditional equivalence result are valuable. However, the main theorem presently leans on an optimization-based step whose existence/consistency is not rigorously established. Tightening the theorem to a conditional statement or adding a theoretical justification for the HDI stage would substantially improve correctness.