$K_4^-$-free triple systems without large stars in the complement
Combinatorics
2025-04-09 v1
Abstract
The -star is the -vertex triple system with edges all of which contain a fixed vertex, and is the unique triple system with four vertices and three edges. We prove that the Ramsey number has order of magnitude . This confirms a conjecture of Conlon, Fox, He, Suk, Verstra\"ete and the first author. It also generalizes the well-known bound of Kim for the graph Ramsey number , as the link of any vertex in a -free triple system is a triangle-free graph. Our method builds on the approach of Guo and Warnke who adapted Kim's lower bound for to the pseudorandom setting.
Keywords
Cite
@article{arxiv.2504.06076,
title = {$K_4^-$-free triple systems without large stars in the complement},
author = {Dhruv Mubayi and Nicholas Spanier},
journal= {arXiv preprint arXiv:2504.06076},
year = {2025}
}
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35 pages