2206.05996
Generalized Evolution Semigroups and General Dichotomies
Nicolae Lupa, Liviu Horia Popescu
correctmedium confidence
- Category
- Not specified
- Journal tier
- Specialist/Solid
- Processed
- Sep 28, 2025, 12:56 AM
- arXiv Links
- Abstract ↗PDF ↗
Audit review
The paper’s Dichotomy Theorem (Theorem 4.4) proves exactly the four-way equivalence and the Green-operator inverse in the μ-time setting using the similarity T = F^{-1} S F and the classical evolution semigroup theory; it also establishes spectral mapping and vertical translation invariance of the generator. The candidate solution reproduces this route: it performs the θ = μ(s) change of variables, shows similarity of semigroups, invokes the classical dichotomy theorem, derives the spectral condition σ(G) ∩ iR = ∅ and invertibility, and reconstructs the inverse via the Green kernel with the μ′ weight. Apart from not explicitly restating the growth assumption ensuring T is a C0-semigroup (condition (29)), the steps and logic coincide with the paper’s proof. See the similarity and spectrum results (32)–(34) and Corollary 3.7, and Theorem 4.4 with formula (37) for the inverse.
Referee report (LaTeX)
\textbf{Recommendation:} minor revisions \textbf{Journal Tier:} specialist/solid \textbf{Justification:} The work presents a robust and conceptually clean generalization of evolution semigroups to accommodate time-varying growth rates via real semiflows, and it leverages similarity to classical evolution semigroups to obtain a sharp dichotomy–spectral characterization. The results are correct and well-situated in the literature. Minor improvements in exposition, especially in assembling standing assumptions and highlighting key invariance mechanisms, would further enhance readability.