arXiv:2607.11408v1
Abstract
The goal of this note is to systematically develop the fundamental arithmetic and combinatorial properties of the sector renormalization operation on rigid rotations. We employ the specific framework of modified continued fractions appropriate for sector renormalization and analyze their properties. By allowing infinite first return times, this framework yields a dynamical compactification characterized by a universal property. We also discuss the corresponding natural extension and introduce the notion of a time (semi-)group. For example, we demonstrate how a bi-infinite tower of sector renormalizations of irrational rotations can be packaged within a single dynamical plane as a cascade of translations. This note will serve as a foundational combinatorial tool for studying the geometric properties of sector renormalizations of holomorphic maps with irrationally indifferent fixed points, particularly neutral quadratic polynomials.
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Audit summary
Not a correctness certificate. A “Correct” result may include yellow typos or minor formal corrections that do not affect substantive soundness. It means this audit found no unresolved substantive error under the stated criteria; it does not replace expert scrutiny or formal verification.
Current report
Detailed mathematical audit
01Statements3 reported findingsCorrect
The modified continued-fraction coding, the two universal characterizations of the compactification, and the natural-extension cascade statements are supported. A missing pair of absolute-value bars in one quantitative convergent estimate is a uniquely determined typo and does not affect these conclusions.
Modified continued fractions conjugate sector renormalization to the shift
Pages 2 and 12–15 · Theorem A, Lemma 3.2, Proposition 3.3, and Theorem 3.4 · arXiv:2607.11408v1
The determinant identity and the uniform ratio bound on successive denominators give convergence of the modified convergents and shrinking symbolic cylinders. The branch formula removes the first symbol. Expansion by at least makes each itinerary fiber a singleton, while the cylinder intervals provide continuity in both directions. Thus is a homeomorphism and .
The segment and dynamical embeddings determine the same minimal compactification
Pages 4 and 18–24 · Propositions 4.4–4.5 and Theorems 4.6–4.8 · arXiv:2607.11408v1
The general orbit-closure construction in has the stated universal factor property. The segment orbit distinguishes the two possible one-sided rational enrichments at every shift, making the induced factor from the symbolic compactification injective. The extended cyclic-order map is itself an embedding, so its orbit factor is also injective. Compactness and the Hausdorff target then upgrade both continuous bijections to homeomorphisms and yield Corollary 4.9.
The natural extension, ordered time group, and translational cascade agree
Pages 26–33 · Propositions 5.2–5.13 · arXiv:2607.11408v1
The slow return times satisfy the usual continuant recurrence, which gives the chronological and left-right positive cones. Mapping each formal return-time generator to translation by respects all relations; injectivity follows because an integral relation between two consecutive generators would force an irrational to be rational. The nested half-strips then project by to the successive sector-renormalization domains, establishing the cascade and triangulation claims.
02Proofs3 reported findingsCorrect
The central arithmetic, compactification, and cascade proofs are correct and complete after immediate-consequence closure. The report records two mechanically determined notation corrections as typos; neither changes a theorem, proof strategy, or overall status.
Absolute-value bars are missing from the convergent-error estimate
Page 14 · Proposition 3.3 and its proof · arXiv:2607.11408v1
The displayed estimate must read Without the bars it is false when : for example, , , and give consecutive convergents and , so the error after the first convergent has negative sign. Lemma 3.2(5) makes the remaining tail smaller than its first term, while the proof already estimates its magnitude. Inserting the bars in the statement and the two corresponding proof lines is therefore the unique intended correction, and the convergence, irrationality, and cylinder-shrinking consequences remain valid.
Full paper, version 1 ↗Several local symbols are mechanically mismatched
Page 15 · proof of Theorem 3.4; page 23 · proof of Theorem 4.7; page 32 · Proposition 5.11 · arXiv:2607.11408v1
In Theorem 3.4, the undefined symbols must be . In Theorem 4.7, the initial unequal pair and the second cases must compare the primed sequence with the unprimed one; the surrounding equations uniquely determine the missing primes. In Proposition 5.11(1), the union of the half-strips is the closed lower half-plane , not , exactly as stated immediately before the display. These are literal notation mismatches with unique local corrections and no mathematical downstream effect.
Full paper, version 1 ↗Central proof chain
Pages 7–33 · Sections 2–5 · arXiv:2607.11408v1
The first-return recurrences, best-approximation estimates, orbit-closure universal property, positive-cone constructions, and exponential projection of the cascade are mutually consistent. Endpoint cases with infinite symbols are handled by the one-point compactification of the alphabet, and the order arguments introduce a new free generator exactly at each parabolic level. No missing nontrivial case remains after the two notation corrections above.
03Novelty0 reported findingsNo non-novelty findings
No non-novelty findings.