English

On Tur\'an numbers for disconnected hypergraphs

Combinatorics 2023-06-13 v2

Abstract

We introduce the following simpler variant of the Tur\'an problem: Given integers n>k>r2n>k>r\geq 2 and m1m\geq 1, what is the smallest integer tt for which there exists an rr-uniform hypergraph with nn vertices, tt edges and mm connected components such that any kk-subset of the vertex set contains at least one edge? We prove some general estimates for this quantity and for its limit, normalized by (nr)\binom{n}{r}, as nn\rightarrow \infty. Moreover, we give a complete solution of the problem for the particular case when k=5k=5, r=3r=3 and m2m\geq 2.

Keywords

Cite

@article{arxiv.2207.10052,
  title  = {On Tur\'an numbers for disconnected hypergraphs},
  author = {Raffaella Mulas and Jiaxi Nie},
  journal= {arXiv preprint arXiv:2207.10052},
  year   = {2023}
}
R2 v1 2026-06-25T01:05:27.987Z