On Partial Vertex Cover and Budgeted Maximum Coverage Problems in Bipartite Graphs

8th IFIP TC 1/WG 2.2 International Conference on Theoretical Computer Science
Graphs are often used to model risk management in various systems. Particularly, Caskurlu et al. in [6] have considered a system which essentially represents a tripartite graph. The goal in this model is to reduce the risk in the system below a predefined risk threshold level. It can be shown that the main goal in this risk management system can be formulated as a Partial Vertex Coverproblem on bipartite graphs. It is well-known that the vertex cover problem is in P on bipartite graphs; however, the computational complexity of the partial vertex cover problem on bipartite graphs is open. In this paper, we show that the partial vertex cover problem is NP-hard on bipartite graphs. Then, we show that the budgeted maximum coverage problem (a problem related to partial vertex cover problem) admits an 8/9-approximation algorithm in the class of bipartite graphs, which matches the integrality gap of a natural LP relaxation. © 2014 IFIP International Federation for Information Processing.