On set systems with strongly restricted intersections
Abstract
Set systems with strongly restricted intersections, called -intersecting families for a vector , were introduced recently as a generalization of several well-studied intersecting families including the classical oddtown and eventown. Given a binary vector , a collection of subsets over an element set is an -intersecting family modulo if for each , all -wise intersections of distinct members in have sizes with the same parity as . Let denote the maximum size of such a family. In this paper, we study the asymptotic behavior of when goes to infinity. We show that if is the maximum integer such that and , then . More importantly, we show that for any constant , as the length goes larger, is upper bounded by for almost all . Equivalently, no matter what is, there are only finitely many satisfying . This answers an open problem raised by Johnston and O'Neill in 2023. All of our results can be generalized to modulo setting for any prime smoothly.
Keywords
Cite
@article{arxiv.2404.08280,
title = {On set systems with strongly restricted intersections},
author = {Xin Wei and Xiande Zhang and Gennian Ge},
journal= {arXiv preprint arXiv:2404.08280},
year = {2024}
}
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12 pages, 0 figure