Summary: Characterizing Planarity
Using Theta Graphs
Dan Archdeacon
Dept. of Math. and Stat.
University of Vermont
Burlington, VT, USA 05405
e­mail: dan.archdeacon@uvm.edu
Jozef Ÿ Sir'aŸn
Department of Mathematics
Faculty of Civil Engineering Slovak Technical University
813 68 Bratislava, Slovakia
e­mail: siran@lux.svf.stuba.sk
September 14, 1997
Abstract
A theta graph is a homeomorph of K 2;3 . In an embedded planar
graph the local rotation at one degree­three vertex of a theta graph
determines the local rotation at the other degree­three vertex. Using
this observation, we give a characterization of planar graphs in terms
of balance in an associated signed graph whose vertices are K 1;3 sub­
graphs and whose edges correspond to theta graphs.

Source: Archdeacon, Dan - Department of Mathematics and Statistics, University of Vermont

Collections: Mathematics