English

Cycles and paths through vertices whose degrees are at least the bipartite-hole-number

Combinatorics 2025-06-12 v1

Abstract

The bipartite-hole-number of a graph GG, denoted by α~(G)\widetilde{\alpha}(G), is the minimum integer kk such that there exist positive integers ss and tt with s+t=k+1s + t = k + 1, satisfying the property that for any two disjoint sets A,BV(G)A, B \subseteq V(G) with A=s|A| = s and B=t|B| = t, there is at least one edge between AA and BB. In 1992, Bollob\'as and Brightwell, and independently Shi, proved that every 22-connected graph of order nn contains a cycle passing through all vertices whose degrees are at least n2\frac{n}{2}. Motivated by their result, we show that in any 22-connected graph of order nn, there exists a cycle containing all vertices whose degrees are at least α~(G)\widetilde{\alpha}(G). Moreover, we prove that for any pair of vertices in a connected graph GG, if their degrees are at least α~(G)+1\widetilde{\alpha}(G) + 1, then there exists a path joining them that contains all vertices whose degrees are at least α~(G)+1\widetilde{\alpha}(G) + 1. The results extend two existing ones.

Keywords

Cite

@article{arxiv.2506.09750,
  title  = {Cycles and paths through vertices whose degrees are at least the bipartite-hole-number},
  author = {Chengli Li and Feng Liu and Yurui Tang},
  journal= {arXiv preprint arXiv:2506.09750},
  year   = {2025}
}

Comments

arXiv admin note: text overlap with arXiv:2504.04493