English

On path-quasar Ramsey numbers

Combinatorics 2015-04-20 v1

Abstract

Let G1G_1 and G2G_2 be two given graphs. The Ramsey number R(G1,G2)R(G_1,G_2) is the least integer rr such that for every graph GG on rr vertices, either GG contains a G1G_1 or G\overline{G} contains a G2G_2. Parsons gave a recursive formula to determine the values of R(Pn,K1,m)R(P_n,K_{1,m}), where PnP_n is a path on nn vertices and K1,mK_{1,m} is a star on m+1m+1 vertices. In this note, we first give an explicit formula for the path-star Ramsey numbers. Secondly, we study the Ramsey numbers R(Pn,K1Fm)R(P_n,K_1\vee F_m), where FmF_m is a linear forest on mm vertices. We determine the exact values of R(Pn,K1Fm)R(P_n,K_1\vee F_m) for the cases mnm\leq n and m2nm\geq 2n, and for the case that FmF_m has no odd component. Moreover, we give a lower bound and an upper bound for the case n+1m2n1n+1\leq m\leq 2n-1 and FmF_m has at least one odd component.

Keywords

Cite

@article{arxiv.1401.3545,
  title  = {On path-quasar Ramsey numbers},
  author = {Binlong Li and Bo Ning},
  journal= {arXiv preprint arXiv:1401.3545},
  year   = {2015}
}

Comments

7 pages

R2 v1 2026-06-22T02:46:00.672Z