English

Tur\'an problems for linear forests and cliques

Combinatorics 2023-05-23 v2

Abstract

Given a graph TT and a family of graphs H\mathcal{H}. The generalized Tur\'an number of H\mathcal{H} is the maximum number of copies of TT in an H\mathcal{H}-free graph on nn vertices, denoted by ex(n,T,H)ex(n, T, \mathcal{H}). Let ex(n,T,H)ex(n, T, \mathcal{H}) denote the maximum number of copies of TT in an nn-vertex H\mathcal{H}-free graph. Recently, Alon and Frankl (arXiv2210.15076) determined the exact values of ex(n,{Kr+1,Ms+1})\rm{ex}(n, \{K_{r+1}, M_{s+1}\}), where Kr+1K_{r+1} and Ms+1M_{s+1} are complete graph on r+1r + 1 vertices and matching of size s+1s + 1, respectively. Ma and Hou (arXiv2301.05625) gave the generalized version of Alon and Frankl's Theorem, which determine the exact values of ex(n,Kr,{Kk+1,Ms+1})ex(n, K_r, \{K_{k+1}, M_{s+1}\}). Zhang determined the exact values of ex(n,Kr,Ln,s)ex(n, K_r, \mathcal{L}_{n, s}), where Ln,s\mathcal{L}_{n, s} be the family of all linear forests of order nn with ss edges. Inspired by the work of Zhang and Ma, in this paper, we determined the exact number of ex(n,{Kr+1,Ln,s})ex(n, \{K_{r+1}, \mathcal{L}_{n, s}\}).

Keywords

Cite

@article{arxiv.2304.11645,
  title  = {Tur\'an problems for linear forests and cliques},
  author = {Tao Fang},
  journal= {arXiv preprint arXiv:2304.11645},
  year   = {2023}
}

Comments

8 pages

R2 v1 2026-06-28T10:14:57.012Z