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Main Authors: Sheng, Junda, Strohmer, Thomas
Format: Preprint
Published: 2022
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Online Access:https://arxiv.org/abs/2205.11677
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author Sheng, Junda
Strohmer, Thomas
author_facet Sheng, Junda
Strohmer, Thomas
contents The stochastic block model is a canonical random graph model for clustering and community detection on network-structured data. Decades of extensive study on the problem have established many profound results, among which the phase transition at the Kesten-Stigum threshold is particularly interesting both from a mathematical and an applied standpoint. It states that no estimator based on the network topology can perform substantially better than chance on sparse graphs if the model parameter is below a certain threshold. Nevertheless, if we slightly extend the horizon to the ubiquitous semi-supervised setting, such a fundamental limitation will disappear completely. We prove that with an arbitrary fraction of the labels revealed, the detection problem is feasible throughout the parameter domain. Moreover, we introduce two efficient algorithms, one combinatorial and one based on optimization, to integrate label information with graph structures. Our work brings a new perspective to the stochastic model of networks and semidefinite program research.
format Preprint
id arxiv_https___arxiv_org_abs_2205_11677
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Semi-Supervised Clustering of Sparse Graphs: Crossing the Information-Theoretic Threshold
Sheng, Junda
Strohmer, Thomas
Machine Learning
Optimization and Control
Probability
60-08 (Primary) 90C35 (Secondary) 90C22
G.3; I.2.6
The stochastic block model is a canonical random graph model for clustering and community detection on network-structured data. Decades of extensive study on the problem have established many profound results, among which the phase transition at the Kesten-Stigum threshold is particularly interesting both from a mathematical and an applied standpoint. It states that no estimator based on the network topology can perform substantially better than chance on sparse graphs if the model parameter is below a certain threshold. Nevertheless, if we slightly extend the horizon to the ubiquitous semi-supervised setting, such a fundamental limitation will disappear completely. We prove that with an arbitrary fraction of the labels revealed, the detection problem is feasible throughout the parameter domain. Moreover, we introduce two efficient algorithms, one combinatorial and one based on optimization, to integrate label information with graph structures. Our work brings a new perspective to the stochastic model of networks and semidefinite program research.
title Semi-Supervised Clustering of Sparse Graphs: Crossing the Information-Theoretic Threshold
topic Machine Learning
Optimization and Control
Probability
60-08 (Primary) 90C35 (Secondary) 90C22
G.3; I.2.6
url https://arxiv.org/abs/2205.11677