Title
Label-connected graphs and the gossip problem
Abstract
A graph with m edges is called label-connected if the edges can be labeled with real numbers in such a way that, for every pair ( u , v ) of vertices, there is a ( u , v )-path with ascending labels. The minimum number of edges of a label-connected graph on n vertices equals the minimum number of calls in the gossip problem for n persons, which is known to be 2 n − 4 for n ⩾ 4. A polynomial characterization of label-connected graphs with n vertices and 2 n − 4 edges is obtained. For a graph G , let θ ( G ) denote the minimum number of edges that have to be added to E ( G ) in order to create a graph with two edge-disjoint spanning trees. It is shown that for a graph G to be label-connected, θ ( G ) ⩽ 2 is necessary and θ ( G ) ⩽ 1 is sufficient. For i = 1, 2, the condition θ ( G ) ⩽ i can be checked in polynomial time. Yet recognizing label-connected graphs is an NP-complete problem. This is established by first showing that the following problem is NP-complete: Given a graph G and two vertices u and v of G , does there exist a ( u, v )-path P in G such that G − E ( P ) is connected?
Year
DOI
Venue
1991
10.1016/0012-365X(91)90068-D
Discrete Mathematics
Keywords
Field
DocType
gossip problem,label-connected graph,polynomial time,np complete problem,spanning tree,connected graph
Pseudoforest,Wheel graph,Discrete mathematics,Graph toughness,Combinatorics,Graph power,Bound graph,Cycle graph,Mathematics,Path graph,Complement graph
Journal
Volume
Issue
ISSN
87
1
Discrete Mathematics
Citations 
PageRank 
References 
7
2.79
1
Authors
3
Name
Order
Citations
PageRank
F. Göbel172.79
J. Orestes Cerdeira2328.45
H. J. Veldman326244.44