7 research outputs found
On the Complexity of {k}-domination for Chordal Graphs
In this work we obtain a new graph class where {k}-DOM is NP-complete: the class of chordal graphs. We also identify some maximal subclasses for which it is polynomial time solvable. By relating this problem with k-DOM, we prove that {k}-DOM is polynomial time solvable for strongly chordal graphs. Besides, by expressing the property involved in k-DOM in Counting Monadic Second- order Logic, we obtain that both problems are linear time solvable for bounded tree-width graphs. In this way we enlarge the family of graphs for which k-DOM is polynomial time solvable.Sociedad Argentina de Inform谩tica e Investigaci贸n Operativ
On the Complexity of {k}-domination for Chordal Graphs
In this work we obtain a new graph class where {k}-DOM is NP-complete: the class of chordal graphs. We also identify some maximal subclasses for which it is polynomial time solvable. By relating this problem with k-DOM, we prove that {k}-DOM is polynomial time solvable for strongly chordal graphs. Besides, by expressing the property involved in k-DOM in Counting Monadic Second- order Logic, we obtain that both problems are linear time solvable for bounded tree-width graphs. In this way we enlarge the family of graphs for which k-DOM is polynomial time solvable.Sociedad Argentina de Inform谩tica e Investigaci贸n Operativ
On the Complexity of {k}-domination for Chordal Graphs
In this work we obtain a new graph class where {k}-DOM is NP-complete: the class of chordal graphs. We also identify some maximal subclasses for which it is polynomial time solvable. By relating this problem with k-DOM, we prove that {k}-DOM is polynomial time solvable for strongly chordal graphs. Besides, by expressing the property involved in k-DOM in Counting Monadic Second- order Logic, we obtain that both problems are linear time solvable for bounded tree-width graphs. In this way we enlarge the family of graphs for which k-DOM is polynomial time solvable.Sociedad Argentina de Inform谩tica e Investigaci贸n Operativ
On the approximability and exact algorithms for vector domination and related problems in graphs
We consider two graph optimization problems called vector domination and
total vector domination. In vector domination one seeks a small subset S of
vertices of a graph such that any vertex outside S has a prescribed number of
neighbors in S. In total vector domination, the requirement is extended to all
vertices of the graph. We prove that these problems (and several variants
thereof) cannot be approximated to within a factor of clnn, where c is a
suitable constant and n is the number of the vertices, unless P = NP. We also
show that two natural greedy strategies have approximation factors ln D+O(1),
where D is the maximum degree of the input graph. We also provide exact
polynomial time algorithms for several classes of graphs. Our results extend,
improve, and unify several results previously known in the literature.Comment: In the version published in DAM, weaker lower bounds for vector
domination and total vector domination were stated. Being these problems
generalization of domination and total domination, the lower bounds of 0.2267
ln n and (1-epsilon) ln n clearly hold for both problems, unless P = NP or NP
\subseteq DTIME(n^{O(log log n)}), respectively. The claims are corrected in
the present versio