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Clément–Steinerberger: Balanced stick breaking

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theorem_2: There is a sequence on the circle and a universal constant c such that for every r ≥ 2 and all large n the largest r-span is at most 1 + c log r/r times the smallest, so μ_r ≤ 1 + c log r/r; proved for the golden-ratio Kronecker and the van der Corput sequences.


François Clément and Stefan Steinerberger, Balanced stick breaking, arXiv:2511.14637v1 (18 November 2025), math.CO, 12 pages. Unrefereed; no journal reference on arXiv and no published version found (Crossref, 2026-09-27). Suggested key [ClSt25].

Edition read. The copy read for this card is arXiv v1, retrieved from https://arxiv.org/pdf/2511.14637v1; 409,063 bytes. The text layer was read. The arXiv record names arXiv's non-exclusive distribution license (arXiv:2511.14637), every other right reserved.

Read status. Claims checked for Theorem 2 and Theorem 3 (p. 2), read clause by clause; the proofs (Section 2 for the van der Corput sequence, pp. 3--9, and Section 3 for the golden-ratio sequence, pp. 9--11) were not read. Unrefereed; nothing here is independently reviewed.

Overview

The paper reads the first nn terms of a sequence (xk)(x_k) on the circle as breaks of a circular stick and asks how unequal rr consecutive pieces must become. Its Theorem 1 (p. 1) restates the three r=1r=1 results of de Bruijn and Erdős (1/log⁡21/\log2, 1/log⁡41/\log4 and the ratio 22), noting that Ostrowski, Schönhage and Toulmin also established them, and Section 1.2 (p. 2) recalls the general-rr lower bound 1+1/r1+1/r of (5.7) and the de Bruijn--Erdős conjecture that 1/r1/r can be replaced by f(r)/rf(r)/r with f(r)→∞f(r)\to\infty, calling the problem "completely open for every r≥2r\ge2".

Theorem 2 (p. 2) gives the upper bound: for some sequence on S1≅[0,1]S^1\cong[0,1] and one universal constant cc, each r∈Nr\in\mathbb N has a threshold, depending on rr, beyond which the largest sum of rr consecutive gaps cut by the first nn terms is at most 1+clog⁡r/r1+c\log r/r times the smallest. Two examples are given, the golden-ratio Kronecker sequence {kφ}\{k\varphi\} and the base-2 van der Corput sequence; the paper says the theorem was conjectured, with the rate possibly optimal, in Brethouwer's 2024 Ph.D. thesis (not read here). Theorem 3 (p. 2) is the input: for either sequence there is a universal cc with ∣#{k≤n:x≤xk≤x+r/n}−r∣≤clog⁡r|\#\{k\le n:x\le x_k\le x+r/n\}-r|\le c\log r for all rr, all large nn (depending on rr) and all x≤1−r/nx\le1-r/n, and the remark after it says the bound holds for all intervals of length r/nr/n on S1S^1, which implies Theorem 2 (p. 3, with the derivation on p. 9). Section 1.3 relates this to Schmidt's theorem, which makes O(log⁡n)O(\log n) the best possible global discrepancy, and to pair correlation. The introduction's stick picture counts n+1n+1 pieces after nn breaks; Theorem 2 is stated on S1S^1, where nn points cut nn arcs, the setting of Problem 1221 (not rechecked here).

Consequence for Problem 1221 (an authored one-line remark): with μr=inf⁡alim sup⁡nMnr(a)/mnr(a)\mu_r=\inf_a\limsup_nM_n^r(a)/m_n^r(a), Theorem 2 gives μr≤1+clog⁡r/r\mu_r\le1+c\log r/r for every r≥2r\ge2 (the printed "for all r∈Nr\in\mathbb N" fails at r=1r=1, where it would give μ1≤1\mu_1\le1 against the de Bruijn--Erdős value μ1=2\mu_1=2), hence r(μr−1)≤clog⁡rr(\mu_r-1)\le c\log r: the third expression of the conjecture can tend to infinity at most at logarithmic rate. Korsky's 2026 preprint claims the matching lower bound μr−1≥log⁡r/(100r)\mu_r-1\ge\log r/(100r) for large rr (Theorem 1.1 there, claimed and unreviewed), which together with this theorem would fix the order of μr−1\mu_r-1.

Bears on. Problem 1221: an upper bound on the growth of the third expression; it bears on the rate, not on whether the conjecture holds. The problem page for 480 lists this preprint among the citing records of the 1981 Chung--Graham announcement as a lead only.

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