English

Intersective sets over abelian groups

Combinatorics 2026-01-06 v3 Number Theory

Abstract

Given a finite abelian group GG and a subset JGJ\subset G with 0J0\in J, let DG(J,N)D_{G}(J,N) be the maximum size of AGNA\subset G^{N} such that the difference set AAA-A and JNJ^{N} have no non-trivial intersection. Recently, this extremal problem has been widely studied for different groups GG and subsets JJ. In this paper, we generalize and improve the relevant results by Alon and by Heged\H{u}s by building a bridge between this problem and cyclotomic polynomials with the help of algebraic graph theory. In particular, we construct infinitely many non-trivial families of GG and JJ for which the current known upper bounds on DG(J,N)D_{G}(J, N) can be improved exponentially.

Keywords

Cite

@article{arxiv.2207.00053,
  title  = {Intersective sets over abelian groups},
  author = {Zixiang Xu and Chi Hoi Yip},
  journal= {arXiv preprint arXiv:2207.00053},
  year   = {2026}
}

Comments

17 pages, revised based on referee comments