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2409.19197

SMOOTHNESS OF LINEARIZATION BY MIXING PARAMETERS OF DICHOTOMY, BOUNDED GROWTH AND PERTURBATION

Álvaro Castañeda, Ignacio Huerta, Gonzalo Robledo

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

Audit review

The paper proves that, under nonuniform dichotomy and bounded-growth hypotheses plus decay/regularity of f, the map η ↦ G(t,η)=η+w*(t;(t,η)) is a C1-diffeomorphism on an initial time interval [0, t̃j), by estimating the Jacobian ∂ηG(t,η)=I−Λ(t,η) with ∥Λ(t,η)∥<1 and invoking Plastock’s global inversion criterion (Theorem 2 with (4.8)–(4.10), and the derivative formula (4.7); see Lemma 3 for the bound on ∂ηy) . The candidate solution recovers the same structure: differentiates under the integral, derives the same type of bound for supη∥∂ηw*∥, and then proves bijectivity via the near-identity contraction argument (I+g with sup∥Dg∥<1), yielding a global C1-diffeomorphism for each fixed t in a possibly explicit interval. Small differences are cosmetic: the paper uses a sequence {θj} to widen the interval and appeals to Plastock; the model uses a single θ and a direct contraction proof and even provides an explicit threshold t̃c. Both approaches are valid and consistent with the paper’s estimates.

Referee report (LaTeX)

\textbf{Recommendation:} minor revisions

\textbf{Journal Tier:} strong field

\textbf{Justification:}

The paper provides rigorous and well-motivated estimates for the Jacobian of the conjugacy map under nonuniform exponential dichotomy and bounded growth, and leverages a sequence of parameters to widen the diffeomorphism time window. The argument is technically sound and situated within current literature. Clarifications on the use of Plastock’s theorem and on when the bounds yield a global-in-time diffeomorphism would improve readability and uptake.