Densest k-Subgraph Approximation on Intersection Graphs
نویسندگان
چکیده
We study approximation solutions for the densest k-subgraph problem (DS-k) on several classes of intersection graphs. We adopt the concept of σ-quasi elimination orders, introduced by Akcoglu et al. [?], generalizing the perfect elimination orders for chordal graphs, and develop a simple O(σ)-approximation technique for graphs admitting such a vertex order. This concept allows us to derive constant factor approximation algorithms for DS-k on many intersection graph classes, such as chordal graphs, circular-arc graphs, claw-free graphs, line graphs of `-hypergraphs, disk graphs, and the intersection graphs of fat geometric objects. We also present a polynomial time approximation scheme for the DS-k problem on unit disk graphs using the shifting technique.
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