Detecting Hierarchical and Overlapping Community Structures in Networks

Community structure can be observed in many natural, biological and social networks. Studies sug- gest that these communities may have organized in a hi- erarchical manner while some communities overlap with others. This paper introduces an algorithm to detect such hierarchical and overlapping community structures in net- works based on the concept of maximal cliques. It intro- duces an alternate modularity for evaluating overlapping community structures. Unlike existing algorithms for de- tecting hierarchical and overlapping community structures, the new algorithm is free of parameter tuning and random seeds. Experiments conducted on two real-world networks show that this algorithm is capable of providing satisfac- tory and consistent results.