English

On the Erd{\H o}s--Hajnal problem in the case of 3-graphs

Combinatorics 2019-07-12 v2

Abstract

Let m(n,r)m(n,r) denote the minimal number of edges in an nn-uniform hypergraph which is not rr-colorable. For the broad history of the problem see [RaiSh]. It is known that for a fixed nn the sequence m(n,r)rn \frac{m(n,r)}{r^n} has a limit. The only trivial case is n=2n=2 in which m(2,r)=(r+12)m(2,r) = \binom{r+1}{2}. In this note we focus on the case n=3n=3. First, we compare the existing methods in this case and then improve the lower bound.

Keywords

Cite

@article{arxiv.1905.02893,
  title  = {On the Erd{\H o}s--Hajnal problem in the case of 3-graphs},
  author = {Danila Cherkashin},
  journal= {arXiv preprint arXiv:1905.02893},
  year   = {2019}
}

Comments

arXiv admin note: text overlap with arXiv:1808.01482