Title
On Hypohamiltonian and Almost Hypohamiltonian Graphs.
Abstract
A graph G is almost hypohamiltonian if G is non-hamiltonian, there exists a vertex w such that G-w is non-hamiltonian, and for any vertex v﾿w the graph G-v is hamiltonian. We prove the existence of an almost hypohamiltonian graph with 17 vertices and of a planar such graph with 39 vertices. Moreover, we find a 4-connected almost hypohamiltonian graph, while Thomassen's question whether 4-connected hypohamiltonian graphs exist remains open. We construct planar almost hypohamiltonian graphs of order n for every n﾿74. During our investigation we draw connections between hypotraceable, hypohamiltonian, and almost hypohamiltonian graphs, and discuss a natural extension of almost hypohamiltonicity. Finally, we give a short argument disproving a conjecture of Chvátal originally disproved by Thomassen, strengthen a result of Araya and Wiener on cubic planar hypohamiltonian graphs, and mention open problems.
Year
DOI
Venue
2015
10.1002/jgt.21815
Journal of Graph Theory
Keywords
Field
DocType
planar
Grinberg's theorem,Topology,Discrete mathematics,Graph,Combinatorics,Hamiltonian (quantum mechanics),Vertex (geometry),Existential quantification,Hypohamiltonian graph,Conjecture,Mathematics
Journal
Volume
Issue
ISSN
79
1
0364-9024
Citations 
PageRank 
References 
2
0.46
8
Authors
1
Name
Order
Citations
PageRank
Carol T. Zamfirescu13815.25