Algorithms and Models for the Web-Graph

Volume 4863 of the series Lecture Notes in Computer Science pp 56-67

Clustering Social Networks

  • Nina MishraAffiliated withDepartment of Computer Science, University of VirginiaSearch Labs, Microsoft Research
  • , Robert SchreiberAffiliated withHP Labs
  • , Isabelle StantonAffiliated withDepartment of Computer Science, University of Virginia
  • , Robert E. TarjanAffiliated withHP LabsDepartment of Computer Science, Princeton University

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Social networks are ubiquitous. The discovery of close-knit clusters in these networks is of fundamental and practical interest. Existing clustering criteria are limited in that clusters typically do not overlap, all vertices are clustered and/or external sparsity is ignored. We introduce a new criterion that overcomes these limitations by combining internal density with external sparsity in a natural way. An algorithm is given for provably finding the clusters, provided there is a sufficiently large gap between internal density and external sparsity. Experiments on real social networks illustrate the effectiveness of the algorithm.