Title
Why Almost All k-Colorable Graphs Are Easy to Color
Abstract
Coloring a k-colorable graph using k colors (k≥3) is a notoriously hard problem. Considering average case analysis allows for better results. In this work we consider the uniform distribution over k-colorable graphs with n vertices and exactly cn edges, c greater than some sufficiently large constant. We rigorously show that all proper k-colorings of most such graphs lie in a single “cluster”, and agree on all but a small, though constant, portion of the vertices. We also describe a polynomial time algorithm that whp finds a proper k-coloring of such a random k-colorable graph, thus asserting that most such graphs are easy to color. This should be contrasted with the setting of very sparse random graphs (which are k-colorable whp), where experimental results show some regime of edge density to be difficult for many coloring heuristics.
Year
DOI
Venue
2010
10.1007/s00224-009-9231-5
Theory Comput. Syst.
Keywords
Field
DocType
cn edge,better result,k-colorable graph,coloring heuristics,proper k-coloring,k-colorable graphs,sparse random graph,average case analysis,proper k-colorings,k-colorable whp,average case analysis · k-colorability · random graphs · spectral analysis,random k-colorable graph,random graph,uniform distribution
Discrete mathematics,Complete coloring,Random regular graph,Edge coloring,Combinatorics,Indifference graph,Chordal graph,Greedy coloring,1-planar graph,Mathematics,Graph coloring
Journal
Volume
Issue
ISSN
46
3
1432-4350
Citations 
PageRank 
References 
6
0.57
26
Authors
3
Name
Order
Citations
PageRank
Amin Coja-Oghlan154347.25
michael krivelevich21688179.90
Dan Vilenchik314313.36