English

The relationship between some nonclassical Ramsey numbers

Combinatorics 2018-01-31 v2

Abstract

The upper (mixed) domination Ramsey number u(m,n)u(m, n)(v(m,n)v(m,n)) is the smallest integer pp such that every 22-coloring of the edges of KpK_p with color red and blue, Γ(B)m\Gamma(B) \geq m or Γ(R)n\Gamma(R) \geq n (β(R)n\beta(R) \geq n); where BB and RR is the subgraph of KpK_p induced by blue and red edges, respectively; Γ(G)\Gamma(G) is the maximum cardinality of a minimal dominating set of a graph GG. First, we prove that v(3,n)=t(3,n)v(3,n)=t(3,n) where t(m,n)t(m,n) is the mixed irredundant Ramsey number i.e. the smallest integer pp such that in every two-coloring (R,B)(R, B) of the edges of KpK_p, IR(B)mIR(B) \geq m or β(R)n\beta(R) \geq n (IR(G)IR(G) is the maximum cardinality of an irredundant set of GG). To achieve this result we use a characterization of the upper domination perfect graphs in terms of forbidden induced subgraphs. By the equality we determine two previously unknown Ramsey numbers, namely v(3,7)=18v(3,7)=18 and v(3,8)=22v(3,8) = 22. In addition, we solve other four remaining open cases from Burger's {\it et. al.} article, which listed all nonclassical Ramsey numbers. We find that u(3,7)=w(7,3)=18u(3,7)=w(7,3)=18, u(3,8)=w(8,3)=21u(3,8) = w(8,3) = 21, where w(m,n)w(m,n) is the irredundant-domination Ramsey number introduced by Burger and Van Vuuren in 2011.

Keywords

Cite

@article{arxiv.1701.08674,
  title  = {The relationship between some nonclassical Ramsey numbers},
  author = {Tomasz Dzido and Renata Zakrzewska},
  journal= {arXiv preprint arXiv:1701.08674},
  year   = {2018}
}

Comments

We found a mistake in the proof of the main theorem. May be the mistake can be corrected, but we can not do it for now. Unfortunately, the remaining theorems in the paper also use the same argument

R2 v1 2026-06-22T18:04:12.908Z