New complexity results for the k-covers problem

The k-covers problem (kCP) asks us to compute a minimum cardinality set of strings of given length k > 1 that covers a given string. It was shown in a recent paper, by reduction to 3-SAT, that the k-covers problem is NP-complete. In this paper we introduce a new problem, that we call the k-bounde...

Full description

Bibliographic Details
Main Authors: Iliopoulos, Costas, Mohamed, M., Smyth, William
Format: Journal Article
Published: Elsevier Inc 2011
Subjects:
Online Access:http://hdl.handle.net/20.500.11937/14681
Description
Summary:The k-covers problem (kCP) asks us to compute a minimum cardinality set of strings of given length k > 1 that covers a given string. It was shown in a recent paper, by reduction to 3-SAT, that the k-covers problem is NP-complete. In this paper we introduce a new problem, that we call the k-bounded relaxed vertex cover problem (RVCPk), which we show is equivalent to k-bounded set cover (SCPk). We show further that kCP is a special case of RVCPk restricted to certain classes Gx,k of graphs that represent all strings x. Thus a minimum k-cover can be approximated to within a factor k in polynomial time. We discuss approximate solutions of kCP, and we state a number of conjectures and open problems related to kCP and Gx,k.