Figure 6

Schematic representation of the projection procedure for bipartite undirected networks. (a) An example of a real bipartite network. For the actual application, the two layers represent verified (turquoise) and unverified (gray) users and a link between nodes of different layers is present if one of the two users retweeted the other one, at least once. (b) Definition of the Bipartite Configuration Model (BiCM) ensemble. Such ensemble includes all possible link realisations, once the number of nodes per layers has been fixed. (c) we focus our attention on nodes i and j, i.e., two verified users, and count the number of common neighbours (in magenta both the nodes and the links to their common neighbours). Subsequently, (d) we compare this measure on the real network with the one on the ensemble: If this overlap is statistically significant with respect to the BiCM, (e) we have a link connecting the two verified users in the projected network. The figure is an adaptation from [11]