Title
Planar Hypohamiltonian Graphs on 40 Vertices
Abstract
A graph is hypohamiltonian if it is not Hamiltonian, but the deletion of any single vertex gives a Hamiltonian graph. Until now, the smallest known planar hypohamiltonian graph had 42 vertices, a result due to Araya and Wiener. That result is here improved upon by 25 planar hypohamiltonian graphs of order 40, which are found through computer-aided generation of certain families of planar graphs with girth 4 and a fixed number of 4-faces. It is further shown that planar hypohamiltonian graphs exist for all orders greater than or equal to 42. If Hamiltonian cycles are replaced by Hamiltonian paths throughout the definition of hypohamiltonian graphs, we get the definition of hypotraceable graphs. It is shown that there is a planar hypotraceable graph of order 154 and of all orders greater than or equal to 156. We also show that the smallest planar hypohamiltonian graph of girth 5 has 45 vertices. (C) 2016 Wiley Periodicals, Inc.
Year
DOI
Venue
2013
10.1002/jgt.22015
JOURNAL OF GRAPH THEORY
Keywords
Field
DocType
graph generation,Grinberg's Theorem,hypohamiltonian graph,hypotraceable graph,planar graph
Grinberg's theorem,Topology,Discrete mathematics,Outerplanar graph,Combinatorics,Coxeter graph,Polyhedral graph,Hypohamiltonian graph,Book embedding,Petersen graph,Pancyclic graph,Mathematics
Journal
Volume
Issue
ISSN
84.0
2.0
0364-9024
Citations 
PageRank 
References 
1
0.39
0
Authors
5
Name
Order
Citations
PageRank
Mohammadreza Jooyandeh1111.72
Brendan D McKay21133145.04
Patric R. J. Östergård360970.61
Ville Pettersson4111.82
Carol T. Zamfirescu53815.25