# Relational flexibility of network elements based on inconsistent community detection

## TL;DR

This paper introduces companionship inconsistency as a new measure to quantify how strongly nodes are affiliated with communities, revealing unique node characteristics and offering insights into network structure and node roles.

## Contribution

It proposes companionship inconsistency as a novel node centrality measure derived from community detection degeneracy, providing a new perspective on node relationships in networks.

## Key findings

- Companionship inconsistency identifies outsider and promiscuous nodes in social networks.
- It diagnoses balance in power transmission in infrastructure networks.
- Discloses intrinsic node properties related to higher-order network organization.

## Abstract

Community identification of network components enables us to understand the mesoscale clustering structure of networks. A number of algorithms have been developed to determine the most likely community structures in networks. Such a probabilistic or stochastic nature of this problem can naturally involve the ambiguity in resultant community structures. More specifically, stochastic algorithms can result in different community structures for each realization in principle. In this study, instead of trying to "solve" this community degeneracy problem, we turn the tables by taking the degeneracy as a chance to quantify how strong companionship each node has with other nodes. For that purpose, we define the concept of companionship inconsistency that indicates how inconsistently a node is identified as a member of a community regarding the other nodes. Analyzing model and real networks, we show that companionship inconsistency discloses unique characteristics of nodes, thus we suggest it as a new type of node centrality. In social networks, for example, companionship inconsistency can classify outsider nodes without firm community membership and promiscuous nodes with multiple connections to several communities. In infrastructure networks such as power grids, it can diagnose how the connection structure is evenly balanced in terms of power transmission. Companionship inconsistency, therefore, abstracts individual nodes' intrinsic property on its relationship to a higher-order organization of the network.