Negative results on characterizing visibility graphs
β Scribed by H. Everett; D. Corneil
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 860 KB
- Volume
- 5
- Category
- Article
- ISSN
- 0925-7721
No coin nor oath required. For personal study only.
β¦ Synopsis
There is no known combinatorial characterization of the visibility graphs of simple polygons. In this paper we show negative results on two different approaches to finding such a characterization. We show that Ghosh's three necessary conditions for a graph to be a visibility graph are not sufficient thus disproving his conjecture. We also show that there is no finite set of minimal forbidden induced subgraphs that characterize visibility graphs.
π SIMILAR VOLUMES
Given a set S = {s 1, s 2, ..., s,,) of vertical line segments, si, sj see each other ff there is a horizontal line segment which intersects them, but does not intersect any other line segment between them. A ws" ibility graph G of vertices {vl, v2, β’ .., v,,} is put into a one-to-one correspondenc
In this paper we give tight lower bounds on the size of the visibility graph, the contracted visibility graph, and the barvisibility graph of n disjoint line segments in the plane, according to their vertex-connectivity.
A dominatin# set for a graph G = (V, E) is a subset of vertices V' c\_ V such that for all v β’ V-V' there exists some uβ’ V' for which {v,u} β’E. The domination number of G is the size of its smallest dominating set(s). For a given graph G with minimum size dominating set D, let mz(G, D) denote the nu