Are networks with more edges easier to synchronize?

TL;DR

This paper investigates how the number and distribution of edges in a network affect its ability to synchronize, revealing that more edges do not necessarily improve synchronizability and that network structure plays a crucial role.

Contribution

The study provides counterexamples showing that increasing edges can decrease synchronizability and highlights the importance of network structure over edge quantity.

Findings

Adding edges does not always enhance synchronizability.

Redundant edges can reduce network synchronizability.

Node betweenness centrality is not a reliable indicator for synchronization.

Abstract

In this paper, the relationship between the network synchronizability and the edge distribution of its associated graph is investigated. First, it is shown that adding one edge to a cycle definitely decreases the network sychronizability. Then, since sometimes the synchronizability can be enhanced by changing the network structure, the question of whether the networks with more edges are easier to synchronize is addressed. It is shown by examples that the answer is negative. This reveals that generally there are redundant edges in a network, which not only make no contributions to synchronization but actually may reduce the synchronizability. Moreover, an example shows that the node betweenness centrality is not always a good indicator for the network synchronizability. Finally, some more examples are presented to illustrate how the network synchronizability varies following the addition of edges, where all the examples show that the network synchronizability globally increases but locally fluctuates as the number of added edges increases.