English

The Tur\'{a}n number of Berge paths

Combinatorics 2026-02-23 v1

Abstract

A Berge path of length kk in an rr-uniform hypergraph is a collection of kk hyperedges h1,,hkh_1,\dots,h_k and k+1k+1 vertices v1,,vk+1v_1,\dots,v_{k+1} such that vi,vi+1hiv_i, v_{i+1}\in h_i for each 1ik1\le i\le k. Gy\H{o}ri, Katona and Lemons [\textit{European J. Combin. 58 (2016) 238--246}] generalized the Erd\H{o}s-Gallai theorem to Berge paths and established bounds for the Tur\'{a}n number of Berge paths. However, these bounds are sharp only when some divisibility conditions hold. Gy\H ori, Lemons, Salia and Zamora [\textit{J. Combin. Theory Ser. B 148 (2021) 239--250}] determined the exact value of the Tur\'{a}n number of Berge paths in the case krk\le r. In this paper, we settle the final open case k>rk>r, thereby completing the determination of the Tur\'{a}n number of Berge paths.

Keywords

Cite

@article{arxiv.2602.17946,
  title  = {The Tur\'{a}n number of Berge paths},
  author = {Xin Cheng and Dániel Gerbner and Hilal Hama Karim and Shujing Miao and Junpeng Zhou},
  journal= {arXiv preprint arXiv:2602.17946},
  year   = {2026}
}

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21 pages