Emergence of network features from multiplexity

TLDR

Many biological and man‑made systems consist of multiple layers of distinct nodes and links, raising the question of whether network structural features arise within individual layers or emerge only when layers are aggregated. This study investigates that question using real‑world data. We analyze the European Air Transportation Multiplex Network, examining how structural measures evolve as airline layers are progressively merged and how layer topology influences the emergence of aggregate network properties.

Abstract

Many biological and man-made networked systems are characterized by the simultaneous presence of different sub-networks organized in separate layers, with links and nodes of qualitatively different types. While during the past few years theoretical studies have examined a variety of structural features of complex networks, the outstanding question is whether such features are characterizing all single layers, or rather emerge as a result of coarse-graining, i.e. when going from the multilayered to the aggregate network representation. Here we address this issue with the help of real data. We analyze the structural properties of an intrinsically multilayered real network, the European Air Transportation Multiplex Network in which each commercial airline defines a network layer. We examine how several structural measures evolve as layers are progressively merged together. In particular, we discuss how the topology of each layer affects the emergence of structural properties in the aggregate network.