Bi-Covering: Covering Edges with Two Small Subsets of Vertices

Autor: Rohit Khandekar, MohammadTaghi Hajiaghayi, Guy Kortsarz, Rajiv Gandhi, Amey Bhangale
Rok vydání: 2017
Předmět:
Zdroj: SIAM Journal on Discrete Mathematics. 31:2626-2646
ISSN: 1095-7146
0895-4801
Popis: We study the following basic problem called Bi-Covering. Given a graph $G(V,E)$, find two (not necessarily disjoint) sets $A\subseteq V$ and $B\subseteq V$ such that $A\cup B = V$ and such that every edge $e$ belongs to either the graph induced by $A$ or the graph induced by $B$. The goal is to minimize $\max\{|A|,|B|\}$. This is the most simple case of the Channel Allocation problem [R. Gandhi et al., Networks, 47 (2006), pp. 225--236]. A solution that outputs $V,\emptyset$ gives ratio at most 2. We show that under a similar strong Unique Games Conjecture by Bansal and Khot [Optimal long code test with one free bit, in Proceedings of the 50th Annual IEEE Symposium on Foundations of Computer Science, FOCS'09, IEEE, 2009, pp. 453--462] there is no $2-\epsilon$ ratio algorithm for the problem, for any constant $\epsilon>0$. Given a bipartite graph, Max-Bi-Clique is a problem of finding the largest $k\times k$ complete bipartite subgraph. For the Max-Bi-Clique problem, a constant factor hardness was known un...
Databáze: OpenAIRE