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2507.13216

Explicit linearization of multi-dimensional germs and vector fields through Ecalle’s tree expansions

Frédéric Fauvet, Frédéric Menous, David Sauzin

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

Audit review

The paper’s Theorems A–B give the composition operator of the linearizing map as a mould–coarmould contraction Ch = ΣF S•(spectrum) DF(a), and the component tree formulas; the proof uses the separativity of S•, the coseparativity of D•, homogeneity, and the identity (qn+∥F∥ − 1)S_{n◁F} = SF (and its vector-field analogue), plus a vanishing lemma. The candidate solution reconstructs the same operator, repackages the tree expansion as a Taylor-substitution operator, and verifies the conjugacy on coordinates using the same homogeneity and root-grafting identities. Aside from a small typo in the uniqueness denominator (should be “≠ 0,” not “≠ 1”), the arguments align closely and are mathematically equivalent to the paper’s method.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The formal results (Theorems A–B) are correct and clearly proved using the armould–coarmould framework, and the later analytic estimates are consistent with the literature. The candidate solution independently rederives the formal part with essentially the same algebraic structure. Minor editorial clarifications would strengthen the exposition, particularly around the vanishing lemma and the role of non-resonance in uniqueness.