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Random Cayley sum hypergraphs and k-fold sumsets
Abstract
We denote by fk(Γ) the largest integer with the property that every subset of a finite abelian group Γ of size at least |Γ| − fk(Γ) is a k-fold sumset. Extending a recent result of Alon and Pham, we prove that fk(Γ) ≤ Õ (n(2k−1)/(4k−3)) holds for all finite abelian groups Γ and integers k ≥ 2, where n = |Γ|. Additionally, we also show that the lower bound fk(Γ) ≥ Ω̃ (n1/k) holds if Γ has no nontrivial element of order dividing k. Our upper bound improves a previous result of Balogh, Liu, and Sharifzadeh, and recovers the bound of Alon and Pham in the case k = 2. The proof relies on a new upper bound for the independence number of random Cayley sum hypergraphs, which may be of independent interest.
Related
BibTeX
@misc{chae2026random,
title = {{Random Cayley sum hypergraphs and $k$-fold sumsets}},
author = {Jihyo Chae and Hyunwoo Lee},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.08629},
eprint = {2610.08629},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.08629},
}
RIS
TY - UNPB
TI - Random Cayley sum hypergraphs and k-fold sumsets
AU - Jihyo Chae
AU - Hyunwoo Lee
PY - 2026
DA - 2026/10/06
PB - arXiv
DO - 10.48550/arxiv.2610.08629
UR - https://arxiv.org/abs/2610.08629
AB - We denote by f_k(Γ) the largest integer with the property that every subset of a finite abelian group Γ of size at least |Γ| − f_k(Γ) is a k-fold sumset. Extending a recent result of Alon and Pham, we prove that f_k(Γ) ≤ Õ (n^(2k−1)/(4k−3)) holds for all finite abelian groups Γ and integers k ≥ 2, where n = |Γ|. Additionally, we also show that the lower bound f_k(Γ) ≥ Ω̃ (n^1/k) holds if Γ has no nontrivial element of order dividing k. Our upper bound improves a previous result of Balogh, Liu, and Sharifzadeh, and recovers the bound of Alon and Pham in the case k = 2. The proof relies on a new upper bound for the independence number of random Cayley sum hypergraphs, which may be of independent interest.
ER -