Title
An algorithm for delta–wye reduction of almost-planar graphs
Abstract
A nonplanar graph G is almost-planar if, for every edge e of G, either G∖e or G∕e is planar. The class of almost-planar graphs were introduced in 1990 by Gubser. In 2015, Wagner proved that every almost-planar graph is delta–wye reducible to K3,3. Moreover, he showed that there exists a reduction sequence in which every graph is almost-planar. We obtain an O(n2) algorithm for Wagner’s result. We also prove that simple, 3-connected, almost-planar graphs have crossing number one and furthermore that these graphs are 3-terminal delta–wye reducible to K6 minus the edges of a triangle, whose vertices are taken as terminals.
Year
DOI
Venue
2020
10.1016/j.dam.2020.06.024
Discrete Applied Mathematics
Keywords
DocType
Volume
Delta–wye transformations,Almost-planar graphs,Delta–wye reducibility,Crossing number
Journal
285
ISSN
Citations 
PageRank 
0166-218X
0
0.34
References 
Authors
0
2
Name
Order
Citations
PageRank
Isidoro Gitler1297.03
Gustavo Sandoval–Angeles200.34