English

Exact minimum codegree thresholds for $K_4^-$-covering and $K_5^-$-covering

Combinatorics 2020-02-04 v1

Abstract

Given two 33-graphs FF and HH, an FF-covering of HH is a collection of copies of FF in HH such that each vertex of HH is contained in at least one copy of them. Let {c2(n,F)c_2(n,F)} be the maximum integer tt such that every 3-graph with minimum codegree greater than tt has an FF-covering. In this note, we answer an open problem of Falgas-Ravry and Zhao (SIAM J. Discrete Math., 2016) by determining the exact value of {c2(n,K4)c_2(n, K_4^-)} and {c2(n,K5)c_2(n, K_5^-)}, where KtK_t^- is the complete 33-graph on tt vertices with one edge removed.

Keywords

Cite

@article{arxiv.2002.00353,
  title  = {Exact minimum codegree thresholds for $K_4^-$-covering and $K_5^-$-covering},
  author = {Lei Yu and Xinmin Hou and Boyuan Liu and Yue Ma},
  journal= {arXiv preprint arXiv:2002.00353},
  year   = {2020}
}

Comments

9 pages

R2 v1 2026-06-23T13:28:03.507Z