2007.00567
DEGREE GAPS FOR MULTIPLIERS AND THE DYNAMICAL ANDRÉ-OORT CONJECTURE
Patrick Ingram
correcthigh confidence
- Category
- Not specified
- Journal tier
- Specialist/Solid
- Processed
- Sep 28, 2025, 12:55 AM
- arXiv Links
- Abstract ↗PDF ↗
Audit review
The paper’s theorem explicitly states the dichotomy: if a family f over X has infinitely many PCF specializations, then for any periodic point P either the multiplier vanishes identically or deg(λf(P)) ≥ hcrit(f) (see the Theorem in the introduction) . The proof uses a combination of local lemmas (including Lemma 4) and the Favre–Gauthier reduction to one infinite critical orbit; in the proof one shows that for a certain set S of places, gcrit,v(f)=0, and then Lemma 4 yields deg(λf(P)) ≥ hcrit(f) . In contrast, the candidate’s Step 2 asserts a general placewise lower bound log^+ |(f^n)'(P)|_v ≥ gcrit,v(f) for any polynomial, which is not in the paper; the only general placewise bound proved is the upper bound log^+ |λf(P)|_v ≤ (d−1) gcrit,v(f) (Proposition 3) . Moreover, the paper shows that without a PCF hypothesis the ratio deg(λf(P))/hcrit(f) can take any rational value in [0,d−1], including values strictly less than 1 (Remark 5) , directly contradicting the candidate’s PCF-free inequality. Hence the model’s proof relies on a false local inequality and drops an essential hypothesis.
Referee report (LaTeX)
\textbf{Recommendation:} minor revisions
\textbf{Journal Tier:} specialist/solid
\textbf{Justification:}
A short, correct note proving a clean degree-gap dichotomy for multipliers in families with infinitely many PCF specializations. It synthesizes existing tools (Favre–Gauthier) with streamlined local arguments. While the result is not a dramatic breakthrough, it is crisp and valuable for arithmetic dynamics. Minor clarifications would improve accessibility.