English

Cooperative coloring of some graph families

Combinatorics 2024-02-19 v3

Abstract

In a family G1,G2,,Gm{G_1, G_2, \ldots, G_m} of graphs sharing the same vertex set VV, a cooperative coloring involves selecting one independent set IiI_i from GiG_i for each i{1,2,,m}i\in \{1,2,\ldots,m\} such that i=1mIi=V\bigcup_{i=1}^m I_i = V. For a graph class G\mathcal{G}, let mG(d)m_{\mathcal{G}}(d) denote the minimum mm required to ensure that any graph family G1,G2,,Gm{G_1, G_2, \ldots, G_m} on the same vertex set, where GiGG_i\in\mathcal{G} and Δ(Gi)d\Delta(G_i)\leq d for each i{1,2,,m}i\in \{1,2,\ldots,m\}, admits a cooperative coloring. For the graph classes T\mathcal{T} (trees) and W\mathcal{W} (wheels), we find that mT(3)=4m_\mathcal{T}(3)=4 and mW(4)=5m_\mathcal{W}(4)=5. Also, we prove that mB(d)=O(log2d)m_{\mathcal{B}^*}(d)=O(\log_2 d) and mL(d)=O(logdloglogd)m_{\mathcal{L}}(d)=O\left(\frac{\log d}{\log\log d}\right), where B\mathcal{B}^* represents the class of graphs whose components are balanced complete bipartite graphs, and L\mathcal{L} represents the class of graphs whose components are generalized theta graphs.

Keywords

Cite

@article{arxiv.2307.07149,
  title  = {Cooperative coloring of some graph families},
  author = {Xuqing Bai and Bi Li and Chuandong Xu and Xin Zhang},
  journal= {arXiv preprint arXiv:2307.07149},
  year   = {2024}
}