English

Ramsey and Gallai-Ramsey numbers for linear forests and kipas

Combinatorics 2024-01-26 v2

Abstract

For two graphs G,HG,H, the \emph{Ramsey number} r(G,H)r(G,H) is the minimum integer nn such that any red/blue edge-coloring of KnK_n contains either a red copy of GG or a blue copy of HH. For two graphs G,HG,H, the \emph{Gallai-Ramsey number} grk(G:H)\operatorname{gr}_k(G:H) is defined as the minimum integer nn such that any kk-edge-coloring of KnK_n must contain either a rainbow copy of GG or a monochromatic copy of HH. In this paper, the classical Ramsey numbers of linear forest versus kipas are obtained. We obtain the exact values of grk(G:H)\operatorname{gr}_k(G:H), where HH is either a path or a kipas and G{K1,3,P4+,P5}G\in\{K_{1,3},P_4^+,P_5\} and P4+P_4^+ is the graph consisting of P4P_4 with one extra edge incident with inner vertex.

Keywords

Cite

@article{arxiv.2401.08942,
  title  = {Ramsey and Gallai-Ramsey numbers for linear forests and kipas},
  author = {Ping Li and Yaping Mao and Ingo Schiermeyer and Yifan Yao},
  journal= {arXiv preprint arXiv:2401.08942},
  year   = {2024}
}