An Implicit Degree Condition for Hamiltonian Cycles

Junqing Cai1,2, Hao Li1,3, Wantao Ning4
1School of Mathematics and Statistics, Lanzhou University, Lanzhou, 730000, P.R. China
2School of Management, Qufu Normal University, Rizhao, 276826, P.R. China
3 L.R.I, UMR 8623, CNRS and Université Paris-Sud 11, F-91405 Orsay, France
4Department of Mathematics, Xidian University, Xian, 710071, P.R China

Abstract

In [11], Zhu, Li, and Deng introduced the definition of implicit degree of a vertex \(v\), denoted by \(\text{id}(v)\). In this paper, we consider implicit degrees and the hamiltonicity of graphs and obtain that:
If \(G\) is a \(2\)-connected graph of order \(n\) such that \(\text{id}(u) + \text{id}(v) \geq n – 1\) for each pair of vertices \(u\) and \(v\) at distance \(2\), then \(G\) is hamiltonian, with some exceptions.