Title
Some classes of graphs that are not PCGs.
Abstract
A graph G=(V,E) is a pairwise compatibility graph (PCG) if there exists an edge-weighted tree T and two non-negative real numbers dmin and dmax, dmin≤dmax, such that each node u∈V is uniquely associated to a leaf of T and there is an edge (u,v)∈E if and only if dmin≤dT(u,v)≤dmax, where dT(u,v) is the sum of the weights of the edges on the unique path PT(u,v) from u to v in T. Understanding which graph classes lie inside and which ones outside the PCG class is an important issue. In this paper we show that some interesting classes of graphs have empty intersection with PCG; they are wheels, strong product of a cycle and P2 and the square of an n node cycle, with n sufficiently large. As a side effect, we show that the smallest planar graph not to be PCG has not 20 nodes, as previously known, but only 8 (it is C82).
Year
DOI
Venue
2019
10.1016/j.tcs.2019.05.017
Theoretical Computer Science
Keywords
DocType
Volume
Phylogenetic tree reconstruction problem,Pairwise compatibility graphs (PCGs),PCG recognition problem,Smallest planar not PCG,Wheel
Journal
791
ISSN
Citations 
PageRank 
0304-3975
0
0.34
References 
Authors
0
4
Name
Order
Citations
PageRank
Pierluigi Baiocchi100.68
Tiziana Calamoneri251146.80
Angelo Monti367146.93
Rossella Petreschi437447.10