An almost complete $t$-intersection theorem for permutations
Combinatorics
2024-05-14 v1 Discrete Mathematics
Abstract
For any and , we determine the size of the largest -intersecting family of permutations, as well as give a sharp stability result. This resolves a conjecture of Ellis, Friedgut and Pilpel (2011) and shows the validity of conjectures of Frankl and Deza (1977) and Cameron (1988) for . We note that, for this range of parameters, the extremal examples are not necessarily trivial, and that our statement is analogous to the celebrated Ahlswede-Khachatrian theorem. The proof is based on the refinement of the method of spread approximations, recently introduced by Kupavskii and Zakharov (2022).
Cite
@article{arxiv.2405.07843,
title = {An almost complete $t$-intersection theorem for permutations},
author = {Andrey Kupavskii},
journal= {arXiv preprint arXiv:2405.07843},
year = {2024}
}