English

Extremal results on Berge disjoint paths

Combinatorics 2026-01-27 v2

Abstract

The well-known Erd\H{o}s-Gallai Theorem gave the Tur\'an number of paths. Bushaw and Kettle generalized this result to consider the Tur\'an number of disjoint paths. Since then, many studies are focused on the Tur\'an number of linear forest. For a graph FF, an rr-uniform hypergraph H\mathcal{H} is a Berge-F\text{Berge-} F if there is a bijection ϕ:E(F)E(H)\phi: E(F)\to E(\mathcal{H}) such that eϕ(e)e\subseteq \phi(e) for each eE(F)e\in E(F). When FF is a path, we call Berge-F\text{Berge-} F a Berge path. The Tur\'an number of Berge paths was initially studied by Gy\H{o}ri, Katona and Lemons. They gave the value of exr(n,Berge-P)\text{ex}_r(n,\text{Berge-}P_\ell) for >r+1\ell>r+1. This result is a generalization of Erd\H{o}s-Galli Theorem. Since then, the Tur\'an number of Berge paths has received widespread attention. Recently, Zhou, Gerbner and Yuan initially studied the Tur\'an number of Berge disjoint paths and for the cases when all the paths have odd length. In this paper, we give a more general result, which gives the exact value of exr(n,Berge-kP)\mathrm{ex}_r(n,\text{Berge-} kP_{\ell}) for all k2k\geq 2, r3r\ge 3, and r+7\ell\geq r+7.

Keywords

Cite

@article{arxiv.2512.23382,
  title  = {Extremal results on Berge disjoint paths},
  author = {Xiamiao Zhao and Yiyan Zhan and Mei Lu},
  journal= {arXiv preprint arXiv:2512.23382},
  year   = {2026}
}
R2 v1 2026-07-01T08:44:10.691Z