War pact model of shrinking networks

TL;DR

This paper introduces the war pact model, a simple framework for understanding shrinking networks, which better captures the structure of real-world systems that decrease in size over time.

Contribution

The paper presents a novel shrinking network model that explains structural properties of real networks and outperforms classical models in certain applications.

Findings

Networks generated by the model exhibit common real-world properties.

The model closely resembles international trade, war, and Bitcoin transaction networks.

Shrinking models offer a new perspective on network evolution.

Abstract

Many real systems can be described by a set of interacting entities forming a complex network. To some surprise, these have been shown to share a number of structural properties regardless of their type or origin. It is thus of vital importance to design simple and intuitive models that can explain their intrinsic structure and dynamics. These can, for instance, be used to study networks analytically or to construct networks not observed in real life. Most models proposed in the literature are of two types. A model can be either static, where edges are added between a fixed set of nodes according to some predefined rule, or evolving, where the number of nodes or edges increases over time. However, some real networks do not grow but rather shrink, meaning that the number of nodes or edges decreases over time. We here propose a simple model of shrinking networks called the war pact model. We show that networks generated in such a way exhibit common structural properties of real networks. Furthermore, compared to classical models, these resemble international trade, correlates of war, Bitcoin transactions and other networks more closely. Network shrinking may therefore represent a reasonable explanation of the evolution of some networks and greater emphasis should be put on such models in the future.