Degree and neighborhood intersection conditions restricted to induced   subgraphs ensuring Hamiltonicity of graphs
  Let claw be the graph $K_{1,3}$. A graph $G$ on $n\geq 3$ vertices is called \emph{o}-heavy if each induced claw of $G$ has a pair of end-vertices with degree sum at least $n$, and 1-heavy if at least one end-vertex of each induced claw of $G$ has degree at least $n/2$. In this note, we show that every 2-connected $o$-heavy or 3-connected 1-heavy graph is Hamiltonian if we restrict Fan-type degree condition or neighborhood intersection condition to certain pairs of vertices in some small induced subgraphs of the graph. Our results improve or extend previous results of Broersma et al., Chen et al., Fan, Goodman & Hedetniemi, Gould & Jacobson, and Shi on the existence of Hamilton cycles in graphs. 
Bo Ning, Shenggui Zhang and Bing Chen
math.CO