“…The study of networks as complex systems has been the subject of intensive research in recent years, both in the physics and statistics communities (see, for example, Kolaczyk, 2009, for a review of the main models, methods, and results). Typically, the datasets considered in that literature exhibit a "natural" or pre-specified network structure, as, for example, world trade fluxes (Serrano and Boguñá, 2003;Barigozzi et al, 2010), co-authorship relations (Newman, 2001), power grids (Watts and Strogatz, 1998), social individual relationships (Zachary, 1977), fluxes of migrants (Fagiolo and Santoni, 2015), or political weblog data (Adamic and Glance, 2005). In all those studies, the network structure (as a collection of vertices and edges) is known, and pre-exists the observations.…”