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A note on maximum independent sets and minimum clique partitions in unit disk graphs and penny graphs: complexity and approximation

Published online by Cambridge University Press:  05 September 2011

Marcia R. Cerioli
Affiliation:
Instituto de Matemática and COPPE-Sistemas, Universidade Federal do Rio de Janeiro, Brazil. Partially supported by CNPq and FAPERJ. [email protected]
Luerbio Faria
Affiliation:
FFP, Universidade do Estado do Rio de Janeiro, Brazil. Partially supported by CNPq. [email protected]
Talita O. Ferreira
Affiliation:
COPPE-Sistemas, Universidade Federal do Rio de Janeiro, Brazil. Supported by CNPq. [email protected]
Fábio Protti
Affiliation:
Instituto de Computação, Universidade Federal Fluminense, Brazil. Partially supported by CNPq and FAPERJ. [email protected]
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Abstract

A unit disk graph is the intersection graphof a family of unit disks in the plane.If the disks do not overlap, it is also a unit coin graph or penny graph.It is known that finding a maximum independent setin a unit disk graph is a NP-hard problem.In this work we extend this result to penny graphs.Furthermore, we prove that finding a minimum clique partitionin a penny graph is also NP-hard, and presenttwo linear-time approximation algorithms for the computation of clique partitions:a 3-approximation algorithm for unit disk graphsand a 2-approximation algorithm for penny graphs.

Type
Research Article
Copyright
© EDP Sciences, 2011

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