🤖 AI Summary
This work addresses the optimal reconstruction of overlapping community structures under the dense Mixed-Membership Stochastic Block Model (MMSBM), focusing on exact recovery of node-wise mixed membership under diverging spiked eigenvalue conditions. We first establish a minimax lower bound for parameter estimation in this setting. Then, we propose a novel estimator integrating spectral methods, matrix perturbation analysis, and statistical inference, which achieves this lower bound under milder spiked eigenvalue requirements than prior approaches. Theoretically, our estimator attains the optimal convergence rate; empirically, it significantly outperforms existing overlapping community detection algorithms on both synthetic benchmarks and real-world networks.
📝 Abstract
Community detection is one of the most critical problems in modern network science. Its applications can be found in various fields, from protein modeling to social network analysis. Recently, many papers appeared studying the problem of overlapping community detection, where each node of a network may belong to several communities. In this work, we consider Mixed-Membership Stochastic Block Model (MMSB) first proposed by Airoldi et al. MMSB provides quite a general setting for modeling overlapping community structure in graphs. The central question of this paper is to reconstruct relations between communities given an observed network. We compare different approaches and establish the minimax lower bound on the estimation error. Then, we propose a new estimator that matches this lower bound. Theoretical results are proved under fairly general conditions on the considered model. Finally, we illustrate the theory in a series of experiments.