Matryoshka and Disjoint Cluster Synchronization of Networks

TL;DR

This paper introduces a new framework for understanding and defining network synchronizability in cluster synchronization, distinguishing between different cluster configurations and stability ranges, with implications for complex network analysis.

Contribution

It provides a novel definition of network synchronizability for cluster synchronization, including classifications like Matryoshka, partially disjoint, and complete disjoint synchronization.

Findings

Defined synchronizability for individual clusters.

Classified cluster synchronization into three types based on stability ranges.

Analyzed the complexity of synchronizability in networks with intertwined and non-intertwined clusters.

Abstract

The main motivation for this paper is to present a definition of network synchronizability for the case of cluster synchronization (CS), in an analogous fashion to Barahona and Pecora for the case of complete synchronization. We find this problem to be substantially more complex than the original one. We distinguish between the two cases of networks with intertwined clusters and no intertwined clusters and between {the two cases that the master stability function is negative either in a bounded range or in an unbounded range of its argument. We first obtain a definition of synchronizability that applies to each individual cluster within a network and then attempt to generalize this definition to the entire network. For CS, the synchronous solution of each cluster may be stable independent of the stability of the other clusters, which results in possibly different ranges in which each cluster synchronizes (isolated CS.) For each pair of clusters, we distinguish between three different cases: Matryoshka Cluster Synchronization (when the range of the stability of the synchronous solution for one cluster is included in that of the other cluster), Partially Disjoint Cluster Synchronization (when the ranges of stability of the synchronous solutions partially overlap), and Complete Disjoint Cluster Synchronization (when the ranges of stability of the synchronous solutions do not overlap.)