Detectability threshold in weighted modular networks

Fuente: arXiv
Guardado en:
Detalles Bibliográficos
Autores principales: Radicchi, Filippo, Silva, Filipi N., Flammini, Alessandro, Fortunato, Santo, Kojaku, Sadamori
Formato: Preprint
Publicado: 2025
Materias:
Acceso en línea:
Etiquetas: Agregar Etiqueta
Sin Etiquetas, Sea el primero en etiquetar este registro!
_version_ 1866911412157153280
author Radicchi, Filippo
Silva, Filipi N.
Flammini, Alessandro
Fortunato, Santo
Kojaku, Sadamori
author_facet Radicchi, Filippo
Silva, Filipi N.
Flammini, Alessandro
Fortunato, Santo
Kojaku, Sadamori
contents We study the necessary condition to detect, by means of spectral modularity optimization, the ground-truth partition in networks generated according to the weighted planted-partition model with two equally sized communities. We analytically derive a general expression for the maximum level of mixing tolerated by the algorithm to retrieve community structure, showing that the value of this detectability threshold depends on the first two moments of the distributions of node degree and edge weight. We focus on the standard case of Poisson-distributed node degrees and compare the detectability thresholds of five edge-weight distributions: Dirac, Poisson, exponential, geometric, and signed Bernoulli. We show that Dirac distributed weights yield the smallest detectability threshold, while exponentially distributed weights increase the threshold by a factor $\sqrt{2}$, with other distributions exhibiting distinct behaviors that depend, either or both, on the average values of the degree and weight distributions. Our results indicate that larger variability in edge weights can make communities less detectable. In cases where edge weights carry no information about community structure, incorporating weights in community detection is detrimental.
format Preprint
id arxiv_https___arxiv_org_abs_2511_00214
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Detectability threshold in weighted modular networks
Radicchi, Filippo
Silva, Filipi N.
Flammini, Alessandro
Fortunato, Santo
Kojaku, Sadamori
Physics and Society
We study the necessary condition to detect, by means of spectral modularity optimization, the ground-truth partition in networks generated according to the weighted planted-partition model with two equally sized communities. We analytically derive a general expression for the maximum level of mixing tolerated by the algorithm to retrieve community structure, showing that the value of this detectability threshold depends on the first two moments of the distributions of node degree and edge weight. We focus on the standard case of Poisson-distributed node degrees and compare the detectability thresholds of five edge-weight distributions: Dirac, Poisson, exponential, geometric, and signed Bernoulli. We show that Dirac distributed weights yield the smallest detectability threshold, while exponentially distributed weights increase the threshold by a factor $\sqrt{2}$, with other distributions exhibiting distinct behaviors that depend, either or both, on the average values of the degree and weight distributions. Our results indicate that larger variability in edge weights can make communities less detectable. In cases where edge weights carry no information about community structure, incorporating weights in community detection is detrimental.
title Detectability threshold in weighted modular networks
topic Physics and Society
url https://arxiv.org/abs/2511.00214