REAL

Random Necklaces Require Fewer Cuts

Alon, N. and Elboim, D. and Pach, János and Tardos, Gábor (2024) Random Necklaces Require Fewer Cuts. SIAM JOURNAL ON DISCRETE MATHEMATICS, 38 (2). pp. 1381-1408. ISSN 0895-4801

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Abstract

It is known that any open necklace with beads of t types, in which the number of beads of each type is divisible by k, can be partitioned by at most (k 1)t cuts into intervals that can be distributed into k collections, each containing the same number of beads of each type. This is tight for all values of k and t. Here, we consider the case of random necklaces, where the number of beads of each type is km. Then the minimum number of cuts required for a "fair"partition with the above property is a random variable X(k, t,m). We prove that for fixed k, t and large m, this random variable is at least (k 1)(t + 1)/2 with high probability. For k = 2, fixed t, and large m, we determine the asymptotic behavior of the probability that X(2, t,m) = s for all values of s ≤ t. We show that this probability is polynomially small when s < (t + 1)/2, is bounded away from zero when s > (t + 1)/2, and decays like Θ (1/ logm) when s = (t + 1)/2. We also show that for large t, X(2, t, 1) is at most (0.4 + o(1))t with high probability and that for large t and large ratio k/ log t, X(k, t, 1) is o(kt) with high probability. © 2024 SIAM.

Item Type: Article
Additional Information: Export Date: 20 September 2024 CODEN: SJDME Funding details: Engineering Research Centers, ERC Funding details: United States-Israel Binational Science Foundation, BSF Funding details: European Research Council, ERC Funding details: Austrian Science Fund, FWF, Z 342-N31, SNN 135643, K-132696 Funding details: Austrian Science Fund, FWF Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH, K-131529 Funding details: Nemzeti Kutatási Fejlesztési és Innovációs Hivatal, NKFIH Funding details: National Science Foundation, NSF, DMS-1855464 Funding details: National Science Foundation, NSF Funding details: 075-15-2019-1926 Funding details: Bloom's Syndrome Foundation, BSF, 2018267 Funding details: Bloom's Syndrome Foundation, BSF Funding text 1: \\\\ast Received by the editors June 30, 2022; accepted for publication (in revised form) January 9, 2024; published electronically April 26, 2024. https://doi.org/10.1137/22M1506699 Funding: The work of the first author was partially supported by National Science Foundation (NSF) grant DMS-1855464 and Binational Science Foundation (BSF) grant 2018267. The work of the third and fourth authors was supported by European Research Council (ERC) Advanced Grant ``GeoScape"" and Russian Federation Megagrant 075-15-2019-1926. The third author was also supported by National Research, Development and Innovation Office (NKFIH) grant K-131529 and Austrian Science Fund (FWF) grant Z 342-N31. The fourth author was also supported by NKFIH grants K-132696 and SNN 135643.
Uncontrolled Keywords: PROPERTY; asymptotic behaviour; Method of moments; Random variables; Random walk; Random walk; High probability; second moment method; Necklace; Necklace; Second moment methods;
Subjects: Q Science / természettudomány > QA Mathematics / matematika
SWORD Depositor: MTMT SWORD
Depositing User: MTMT SWORD
Date Deposited: 31 Dec 2024 05:28
Last Modified: 31 Dec 2024 05:28
URI: https://real.mtak.hu/id/eprint/212575

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