2105.10055
REALIZING POLYNOMIAL PORTRAITS
William Floyd, Daniel Kim, Sarah Koch, Walter Parry, Edgar Saenz
correctmedium confidence
- Category
- Not specified
- Journal tier
- Strong Field
- Processed
- Sep 28, 2025, 12:56 AM
- arXiv Links
- Abstract ↗PDF ↗
Audit review
The paper proves the existence theorem: every abstract polynomial portrait Γ is realized by a polynomial f with Γ_f ≃ Γ (stated as Theorem 1 and outlined explicitly: construct an unobstructed topological polynomial via a finite subdivision rule and then apply Thurston’s characterization; the fixed vertex of full degree ensures the rational map is a polynomial) . The model solution cites precisely this FKKPS result and sketches the standard three-step route (topological model → no Levy obstruction → Thurston straightening to a polynomial). One small mismatch: the model attributes the construction to a “rose map,” whereas the paper’s proof of Theorem 1 uses a finite-subdivision-rule construction to forbid Levy cycles (via Lemma 6 and the ‘stickers’/new edges argument) rather than the rose-map setup used later for constructing obstructed examples . Substantively, however, both rely on the same unobstructedness + Thurston pipeline, so the conclusions agree.
Referee report (LaTeX)
\textbf{Recommendation:} minor revisions
\textbf{Journal Tier:} strong field
\textbf{Justification:}
The work gives a comprehensive and constructive answer to the realization problem for polynomial portraits and a clear classification of when portraits are completely unobstructed. The methods are well integrated with Thurston theory, and the exposition largely succeeds, with only minor typos and a few places where distinguishing the roles of finite subdivision rules versus rose maps would aid readers.