Journal of the Operations Research Society of China ›› 2025, Vol. 13 ›› Issue (1): 297-312.doi: 10.1007/s40305-023-00494-0

Previous Articles     Next Articles

Ramsey Numbers of Stripes Versus Trees and Unicyclic Graphs

Si-Nan Hu1, Yue-Jian Peng2   

  1. 1 School of Mathematics and Statistics, Changsha University of Science and Technology, Changsha 410114, Hunan, China;
    2 School of Mathematics, Hunan University, Changsha 410082, Hunan, China
  • Received:2022-10-15 Revised:2023-05-09 Online:2025-03-30 Published:2025-03-20
  • Contact: Yue-Jian Peng,Si-Nan Hu E-mail:ypeng1@hnu.edu.cn;husinan7@163.com

Abstract: For graphs G and H, the Ramsey number R(G, H) is the minimum integer N such that any coloring of the edges of the complete graph KN in red or blue yields a red G or a blue H. Denote the union of t disjoint copies of a graph F by tF. We call tK2 a stripe. In this paper, we completely determine Ramsey numbers of stripes versus trees and unicyclic graphs. Our result also implies that a tree is tK2-good if and only if the independence number of this tree is no less than t. As an application, we improve the known Ramsey numbers of stars versus fan graphs. Moreover, we determine the bipartite Ramsey numbers of a connected bipartite graph versus stripes.

Key words: Ramsey number, Bipartite Ramsey number, Stripes, Tree, Unicyclic graph

CLC Number: