Title
On the complexity of some colorful problems parameterized by treewidth
Abstract
We study the complexity of several coloring problems on graphs, parameterized by the treewidth t of the graph: (1) The list chromatic number χl(G) of a graph G is defined to be the smallest positive integer r, such that for every assignment to the vertices v of G, of a list Lv of colors, where each list has length at least r, there is a choice of one color from each vertex list Lv yielding a proper coloring of G. We show that the problem of determining whether χl(G) ≤ r, the LIST CHROMATIC NUMBER problem, is solvable in linear time for every fixed treewidth bound t. The method by which this is shown is new and of general applicability. (2) The LIST COLORING problem takes as input a graph G, together with an assignment to each vertex v of a set of colors Cv. The problem is to determine whether it is possible to choose a color for vertex v from the set of permitted colors Cv, for each vertex, so that the obtained coloring of G is proper. We show that this problem is W[1]-hard, parameterized by the treewidth of G. The closely related PRECOLORING EXTENSION problem is also shown to be W[1]-hard, parameterized by treewidth. (3) An equitable coloring of a graph G is a proper coloring of the vertices where the numbers of vertices having any two distinct colors differs by at most one. We show that the problem is hard for W[1], parameterized by (t, r). We also show that a list-based variation, LIST EQUITABLE COLORING is W[1]-hard for trees, parameterized by the number of colors on the lists.
Year
DOI
Venue
2011
10.1016/j.ic.2010.11.026
Information & Computation
Keywords
Field
DocType
precoloring extension problem,colorful problem,list l,coloring problem,vertices v,colors c,vertex v,bounded treewidth,equitable coloring,graph g,proper coloring,parameterized complexity,graph coloring,list chromatic number,linear time,list coloring
Complete coloring,Edge coloring,Discrete mathematics,Combinatorics,Fractional coloring,List coloring,Brooks' theorem,Greedy coloring,Mathematics,Graph coloring,Equitable coloring
Journal
Volume
Issue
ISSN
209
2
Information and Computation
Citations 
PageRank 
References 
37
1.51
23
Authors
7
Name
Order
Citations
PageRank
Michael R. Fellows14138319.37
Fedor V. Fomin23139192.21
Daniel Lokshtanov31438110.05
Frances A. Rosamond468434.52
Saket Saurabh52023179.50
Stefan Szeider6134199.97
Carsten Thomassen72379380.35