Emergence of network features from multiplexity

TL;DR

This paper investigates whether structural features of multilayer networks are inherent to individual layers or emerge from the aggregation process, using real-world airline network data to analyze how properties change when layers are merged.

Contribution

It provides empirical insights into the emergence of network features from multilayer to aggregate representations, focusing on the European Air Transportation network.

Findings

Structural properties evolve as layers are merged.

Layer topology influences the emergence of features.

Multilayer features can differ from aggregate network features.

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.