2105.05406
On Structure of Topological Entropy for Tree-Shift of Finite Type
Jung-Chao Ban, Chih-Hung Chang, Wen-Guei Hu, Yu-Liang Wu
correcthigh confidence
- Category
- Not specified
- Journal tier
- Specialist/Solid
- Processed
- Sep 28, 2025, 12:56 AM
- arXiv Links
- Abstract ↗PDF ↗
Audit review
The paper’s Theorem 5.1 constructs a layered strongly connected graph G_{y_l;N} with |V_i| = n_i and edges from V_i to V_{i+1}, deriving the exact product p_{G;1}(n) and the limit h(T_G) → μ(d)_{y_l}, then proving density in [(d−1)log 2, ∞) via a careful control of cyclic shifts (notably y_1 ≥ 2^d and restricted digits) . The candidate solution replaces this by a “base–clone” two-layer gadget. That gadget forces every other tree layer to be inert (outdegree 1), so its layer-by-layer counting formula log N(n) = ∑ d^{t+1} log w_{i+t} is incorrect for the proposed graph; the ensuing error bounds and the limit μ(d)_{y_l} therefore do not follow. In addition, the model’s density step does not justify that the maximizing cyclic shift equals the chosen digit order, a point handled explicitly in the paper.
Referee report (LaTeX)
\textbf{Recommendation:} minor revisions
\textbf{Journal Tier:} specialist/solid
\textbf{Justification:}
The manuscript convincingly shows that entropies of irreducible hom Markov tree-shifts are dense in a large half-line and explains how reducibility can strictly increase entropy. The main construction is natural and technically clean, with careful use of layered graphs and weighted limits. A few points of notation and typesetting could be clarified for readability, but the mathematical content appears correct and significant for the study of tree-shifts.