Abstract
‘A fruitful approach’ shows how the vertices and edges of graphs identify relations between things and how Jacob Moreno became the first to apply this to the analysis of social networks using sociometry. The Random Graph model of Paul Erdős and Alfréd Rényi is now a benchmark of comparison for all networks, since any deviations from this model suggest the presence of some kind of structure, order, regularity, and non-randomness in many real-world networks. Networks try to explain how a set of isolated elements are transformed, through a pattern of interactions, into groups and communities. In all cases where this pattern is relevant, the network approach provides essential insights.