Approximating dominating set on intersection graphs of rectangles and L-frames
We consider the Minimum Dominating Set (MDS) problem on the intersection graphs of geometric objects. Even for simple and widely-used geometric objects such as rectangles, no sub-logarithmic approximation is known for the problem and (perhaps surprisingly) the problem is NP-hard even when all the rectangles are “anchored” at a diagonal line with slope -1 (Pandit, CCCG 2017). In this paper, we first show that for any > 0, there exists a (2+)-approximation algorithm for the MDS problem on “diagonal-anchored” rectangles, providing the first O(1)approximation for the problem on a non-trivial subclass of rectangles. It is not hard to see that the MDS problem on “diagonal-anchored” rectangles is the same as the MDS problem on “diagonal-anchored” L-frames: the union of a vertical and a horizontal line segment that share an endpoint. As such, we also obtain a (2 + )-approximation for the problem with “diagonal-anchored” L-frames. On the other hand, we show that the problem is APX-hard in case the input L-frames intersect the diagonal, or the horizontal segments of the L-frames intersect a vertical line. However, as we show, the problem is linear-time solvable in case the L-frames intersect a vertical as well as a horizontal line. Finally, we consider the MDS problem in the so-called “edge intersection model” and obtain a number of results, answering two questions posed by Mehrabi (WAOA 2017).
|Keywords||Approximation schemes, APX-hardness, Local search, Minimum dominating set, Rectangles and L-frames|
|Conference||43rd International Symposium on Mathematical Foundations of Computer Science, MFCS 2018|
Bandyapadhyay, S. (Sayan), Maheshwari, A, Mehrabi, S. (Saeed), & Suri, S. (Subhash). (2018). Approximating dominating set on intersection graphs of rectangles and L-frames. In Leibniz International Proceedings in Informatics, LIPIcs. doi:10.4230/LIPIcs.MFCS.2018.37