Complex Networks
Graph theory was initiated by Euler in the eighteenth century. In mathematics, graph theory consolidated itself in the following decades and centuries. However, it was only until a little more than a decade ago that an explosion of research and applications ocurred, in what is now referred to as network science [23, 3, 17, 16]. In particular, the networks have become a central tool in the study of complex systems [2, 14, 21, 15]. The language of “nodes and edges” provided by networks has proven to be very illustrative to model elements of a system (nodes) and their interactions (edges). Having a language that describes interactions is essential for a non-reductionist science [10]. The relevance of the study complex networks [18, 7, 4, 8] resides in the fact that so many real networks do not have a trivial topology. It follows that their properties are also not trivial, opening many research avenues. Examples of