Towards a Better Understanding of the Characteristics of Fractal Networks

TL;DR

This paper investigates the origins and characteristics of fractal properties in complex networks, analyzing both models and real-world data to identify universal features and clarify their underlying mechanisms.

Contribution

It provides a systematic review and comprehensive analysis of network properties associated with fractality across multiple models and real networks, clarifying their universal presence.

Findings

Fractal networks exhibit specific universal properties.

Certain network characteristics are artifacts, not fundamental to fractality.

The study clarifies mechanisms underlying network fractality.

Abstract

The fractal nature of complex networks has received a great deal of research interest in the last two decades. Similarly to geometric fractals, the fractality of networks can also be defined with the so-called box-covering method. A network is called fractal if the minimum number of boxes needed to cover the entire network follows a power-law relation with the size of the boxes. The fractality of networks has been associated with various network properties throughout the years, for example, disassortativity, repulsion between hubs, long-range-repulsive correlation, and small edge betweenness centralities. However, these assertions are usually based on tailor-made network models and on a small number of real networks, hence their ubiquity is often disputed. Since fractal networks have been shown to have important properties, such as robustness against intentional attacks, it is in dire need to uncover the underlying mechanisms causing fractality. Hence, the main goal of this work is to get a better understanding of the origins of fractality in complex networks. To this end, we systematically review the previous results on the relationship between various network characteristics and fractality. Moreover, we perform a comprehensive analysis of these relations on five network models and a large number of real-world networks originating from six domains. We clarify which characteristics are universally present in fractal networks and which features are just artifacts or coincidences.