Fundamental Limits of Community Detection in Contextual Multi-Layer Stochastic Block Models

Fuente: arXiv
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Autores principales: Gong, Shuyang, Huang, Dong, Li, Zhangsong
Formato: Preprint
Publicado: 2026
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author Gong, Shuyang
Huang, Dong
Li, Zhangsong
author_facet Gong, Shuyang
Huang, Dong
Li, Zhangsong
contents We consider the problem of community detection from the joint observation of a high-dimensional covariate matrix and $L$ sparse networks, all encoding noisy, partial information about the latent community labels of $n$ subjects. In the asymptotic regime where the networks have constant average degree and the number of features $p$ grows proportionally with $n$, we derive a sharp threshold under which detecting and estimating the subject labels is possible. Our results extend the work of \cite{MN23} to the constant-degree regime with noisy measurements, and also resolve a conjecture in \cite{YLS24+} when the number of networks is a constant. Our information-theoretic lower bound is obtained via a novel comparison inequality between Bernoulli and Gaussian moments, as well as a statistical variant of the ``recovery to chi-square divergence reduction'' argument inspired by \cite{DHSS25}. On the algorithmic side, we design efficient algorithms based on counting decorated cycles and decorated paths and prove that they achieve the sharp threshold for both detection and weak recovery. In particular, our results show that there is no statistical-computational gap in this setting.
format Preprint
id arxiv_https___arxiv_org_abs_2602_08173
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Fundamental Limits of Community Detection in Contextual Multi-Layer Stochastic Block Models
Gong, Shuyang
Huang, Dong
Li, Zhangsong
Statistics Theory
Information Theory
Machine Learning
Probability
Primary 62F15, 68Q87, Secondary 05C85, 90C35
We consider the problem of community detection from the joint observation of a high-dimensional covariate matrix and $L$ sparse networks, all encoding noisy, partial information about the latent community labels of $n$ subjects. In the asymptotic regime where the networks have constant average degree and the number of features $p$ grows proportionally with $n$, we derive a sharp threshold under which detecting and estimating the subject labels is possible. Our results extend the work of \cite{MN23} to the constant-degree regime with noisy measurements, and also resolve a conjecture in \cite{YLS24+} when the number of networks is a constant. Our information-theoretic lower bound is obtained via a novel comparison inequality between Bernoulli and Gaussian moments, as well as a statistical variant of the ``recovery to chi-square divergence reduction'' argument inspired by \cite{DHSS25}. On the algorithmic side, we design efficient algorithms based on counting decorated cycles and decorated paths and prove that they achieve the sharp threshold for both detection and weak recovery. In particular, our results show that there is no statistical-computational gap in this setting.
title Fundamental Limits of Community Detection in Contextual Multi-Layer Stochastic Block Models
topic Statistics Theory
Information Theory
Machine Learning
Probability
Primary 62F15, 68Q87, Secondary 05C85, 90C35
url https://arxiv.org/abs/2602.08173