Majorization and additive tuples in ℤ2n
Abstract
Majorization is a fundamental tool for comparing how "spread out" the entries of two vectors are. Key majorization results were obtained for the integers by Hardy, Littlewood and Pólya and for ℤp by Lev. In this paper, we establish a powerful majorization theorem in ℤ2n that is an analogue of Lev's result in ℤp. Our proof is based on a novel use of a compression argument that optimizes certain sums of additive representation counts. Our majorization theorem has several applications in additive combinatorics. We resolve the question: given subsets A1,…,Ak⊆ℤ2n of prescribed sizes, when is the function rk(A1,…,Ak), which counts the number of additive k-tuples in A1×⋯× Ak, maximized? We establish the corresponding minimization result and a characterization of all extremizers for rk(A,…,A) when k is odd. When k=3, this quantity is the number of Schur triples in A; as a special case, we recover a theorem of Samotij and Sudakov on Schur triples. We also obtain a convexity inequality and use it to prove an analogue of Pollard's theorem that strengthens and extends a well-known result of Bollobás and Leader in the ℤ2n setting.
Related
BibTeX
@misc{huczynska2026majorization,
title = {{Majorization and additive tuples in $\mathbbZ_2^n$}},
author = {Sophie Huczynska and Firdavs Rakhmonov and Chi Hoi Yip},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.07855},
eprint = {2609.07855},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.07855},
}
RIS
TY - UNPB
TI - Majorization and additive tuples in ℤ_2^n
AU - Sophie Huczynska
AU - Firdavs Rakhmonov
AU - Chi Hoi Yip
PY - 2026
DA - 2026/09/07
PB - arXiv
DO - 10.48550/arxiv.2609.07855
UR - https://arxiv.org/abs/2609.07855
AB - Majorization is a fundamental tool for comparing how "spread out" the entries of two vectors are. Key majorization results were obtained for the integers by Hardy, Littlewood and Pólya and for ℤ_p by Lev. In this paper, we establish a powerful majorization theorem in ℤ_2^n that is an analogue of Lev's result in ℤ_p. Our proof is based on a novel use of a compression argument that optimizes certain sums of additive representation counts. Our majorization theorem has several applications in additive combinatorics. We resolve the question: given subsets A_1,…,A_k⊆ℤ_2^n of prescribed sizes, when is the function r_k(A_1,…,A_k), which counts the number of additive k-tuples in A_1×⋯× A_k, maximized? We establish the corresponding minimization result and a characterization of all extremizers for r_k(A,…,A) when k is odd. When k=3, this quantity is the number of Schur triples in A; as a special case, we recover a theorem of Samotij and Sudakov on Schur triples. We also obtain a convexity inequality and use it to prove an analogue of Pollard's theorem that strengthens and extends a well-known result of Bollobás and Leader in the ℤ_2^n setting.
ER -