English

Ramsey goodness of paths

Combinatorics 2016-06-28 v3

Abstract

Given a pair of graphs GG and HH, the Ramsey number R(G,H)R(G,H) is the smallest NN such that every red-blue coloring of the edges of the complete graph KNK_N contains a red copy of GG or a blue copy of HH. If graph GG is connected, it is well known and easy to show that R(G,H)(G1)(χ(H)1)+σ(H)R(G,H) \geq (|G|-1)(\chi(H)-1)+\sigma(H), where χ(H)\chi(H) is the chromatic number of HH and σ\sigma the size of the smallest color class in a χ(H)\chi(H)-coloring of HH. A graph GG is called HH-good if R(G,H)=(G1)(χ(H)1)+σ(H)R(G,H)= (|G|-1)(\chi(H)-1)+\sigma(H). The notion of Ramsey goodness was introduced by Burr and Erd\H{o}s in 1983 and has been extensively studied since then. In this short note we prove that nn-vertex path PnP_n is HH-good for all n4Hn\geq 4|H|. This proves in a strong form a conjecture of Allen, Brightwell, and Skokan.

Keywords

Cite

@article{arxiv.1512.07874,
  title  = {Ramsey goodness of paths},
  author = {Alexey Pokrovskiy and Benny Sudakov},
  journal= {arXiv preprint arXiv:1512.07874},
  year   = {2016}
}

Comments

4 pages

R2 v1 2026-06-22T12:17:43.138Z