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Main Authors: Bianco, Leonardo Martins, Keribin, Christine, Naulet, Zacharie
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2506.03657
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author Bianco, Leonardo Martins
Keribin, Christine
Naulet, Zacharie
author_facet Bianco, Leonardo Martins
Keribin, Christine
Naulet, Zacharie
contents Community detection is a fundamental task in graph analysis, with methods often relying on fitting models like the Stochastic Block Model (SBM) to observed networks. While many algorithms can accurately estimate SBM parameters when the input graph is a perfect sample from the model, real-world graphs rarely conform to such idealized assumptions. Therefore, robust algorithms are crucial-ones that can recover model parameters even when the data deviates from the assumed distribution. In this work, we propose SubSearch, an algorithm for robustly estimating SBM parameters by exploring the space of subgraphs in search of one that closely aligns with the model's assumptions. Our approach also functions as an outlier detection method, properly identifying nodes responsible for the graph's deviation from the model and going beyond simple techniques like pruning high-degree nodes. Extensive experiments on both synthetic and real-world datasets demonstrate the effectiveness of our method.
format Preprint
id arxiv_https___arxiv_org_abs_2506_03657
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle SubSearch: Robust Estimation and Outlier Detection for Stochastic Block Models via Subgraph Search
Bianco, Leonardo Martins
Keribin, Christine
Naulet, Zacharie
Machine Learning
Community detection is a fundamental task in graph analysis, with methods often relying on fitting models like the Stochastic Block Model (SBM) to observed networks. While many algorithms can accurately estimate SBM parameters when the input graph is a perfect sample from the model, real-world graphs rarely conform to such idealized assumptions. Therefore, robust algorithms are crucial-ones that can recover model parameters even when the data deviates from the assumed distribution. In this work, we propose SubSearch, an algorithm for robustly estimating SBM parameters by exploring the space of subgraphs in search of one that closely aligns with the model's assumptions. Our approach also functions as an outlier detection method, properly identifying nodes responsible for the graph's deviation from the model and going beyond simple techniques like pruning high-degree nodes. Extensive experiments on both synthetic and real-world datasets demonstrate the effectiveness of our method.
title SubSearch: Robust Estimation and Outlier Detection for Stochastic Block Models via Subgraph Search
topic Machine Learning
url https://arxiv.org/abs/2506.03657