Title: Core of communities in bipartite networks,
Abstract: We use the information present in a bipartite network to detect cores of
communities of each set of the bipartite system. Cores of communities are found
by investigating statistically validated projected networks obtained using
information present in the bipartite network. Cores of communities are highly
informative and robust with respect to the presence of errors or missing
entries in the bipartite network. We assess the statistical robustness of cores
by investigating an artificial benchmark network, the co-authorship network,
and the actor-movie network. The accuracy and precision of the partition
obtained with respect to the reference partition are measured in terms of the
adjusted Rand index and of the adjusted Wallace index respectively. The
detection of cores is highly precise although the accuracy of the methodology
can be limited in some cases.