Can visibility graphs be represented compactly?

Pankaj K. Agarwal, Noga Alon, Boris Aronov, Subhash Suri

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Scopus citations


We consider the problem of representing the visibility graph of line segments as a union of cliques and bipartite cliques. Given a graph G, a family G = {G1, G2,..., Gk} is called a clique cover of G if (i) each Gi is a clique or a bipartite clique, and (ii) the union of Gi is G. The size of the clique cover G is defined as Σik=1 ni, where ni is the number of vertices in Gi. Our main result is that there exist visibility graphs of n nonintersecting line segments in the plane whose smallest clique cover has size Ω(n2/log2 n). An upper bound of O(n2/log n) on the clique cover follows from a well-known result in extremal graph theory. On the other hand, we show that the visibility graph of a simple polygon always admits a clique cover a size O(n log3 n), and that there are simple polygons whose visibility graphs require a clique cover of size Ω(n log n).

Original languageEnglish (US)
Title of host publicationProceedings of the 9th Annual Symposium on Computational Geometry
PublisherPubl by ACM
Number of pages10
ISBN (Print)0897915828, 9780897915823
StatePublished - 1993
Externally publishedYes
EventProceedings of the 9th Annual Symposium on Computational Geometry - San Diego, CA, USA
Duration: May 19 1993May 21 1993

Publication series

NameProceedings of the 9th Annual Symposium on Computational Geometry


OtherProceedings of the 9th Annual Symposium on Computational Geometry
CitySan Diego, CA, USA

All Science Journal Classification (ASJC) codes

  • General Engineering


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