The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes

[eng] Over the past few decades, the use of complex networks to describe the properties of systems of many interacting particles has become widespread in many fields of science. Surprisingly, networks from disparate disciplines share a wide range of basic properties, such as small worldness, high le...

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Autor: Kolk, Jasper Eibertus van der
Tipo de recurso: tesis doctoral
Estado:Versión publicada
Fecha de publicación:2024
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/218518
Acceso en línea:https://hdl.handle.net/2445/218518
http://hdl.handle.net/10803/693572
Access Level:acceso abierto
Palabra clave:Sistemes complexos
Geometria
Xarxes (Matemàtica)
Complex systems
Geometry
Nets (Mathematics)
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oai_identifier_str oai:diposit.ub.edu:2445/218518
network_acronym_str ES
network_name_str España
repository_id_str
dc.title.none.fl_str_mv The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
title The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
spellingShingle The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
Kolk, Jasper Eibertus van der
Sistemes complexos
Geometria
Xarxes (Matemàtica)
Complex systems
Geometry
Nets (Mathematics)
title_short The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
title_full The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
title_fullStr The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
title_full_unstemmed The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
title_sort The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical Processes
dc.creator.none.fl_str_mv Kolk, Jasper Eibertus van der
author Kolk, Jasper Eibertus van der
author_facet Kolk, Jasper Eibertus van der
author_role author
dc.contributor.none.fl_str_mv Boguñá, Marián
Serrano Moral, Ma. Ángeles (María Ángeles)
Universitat de Barcelona. Facultat de Física
dc.subject.none.fl_str_mv Sistemes complexos
Geometria
Xarxes (Matemàtica)
Complex systems
Geometry
Nets (Mathematics)
topic Sistemes complexos
Geometria
Xarxes (Matemàtica)
Complex systems
Geometry
Nets (Mathematics)
description [eng] Over the past few decades, the use of complex networks to describe the properties of systems of many interacting particles has become widespread in many fields of science. Surprisingly, networks from disparate disciplines share a wide range of basic properties, such as small worldness, high levels of clustering and broad degree distributions. One of the most promising frameworks to explain this observation is that of network geometry, where nodes are assumed to live in some underlying metric space that conditions their connectivity. The fact that this approach can reproduce all the basic network properties and symmetries as well as produce strong results in practical tasks such as community detection and link prediction has led many to wonder if there is a way to determine if real networks are indeed geometric in nature. However, these studies do not contemplate the fact that the transition between non-geometric and geometric networks might not be sharp. In this thesis we study the effect the effect of the underlying metric space on the complex network for different geometric coupling strengths. We show that three different regimes can be identified: In the non-geometric regime, where the coupling is extremely weak, results are similar to those of the configuration model, which is explicitly non-geometric. Increasing the coupling slightly leads us to the quasi-geometric regime, where the scaling of the clustering coefficient with the system size is extremely slow, leading to significant levels of this quantity for finite systems. Additionally, we show that, here, geometric information can be extracted from the topology alone through network embedding, and that it is essential for obtaining self-similar network replicas through geometric renormalization. Finally, we study a large number of empirical networks and show that they are best described in the quasi-geometric regime. Increasing the coupling further leads us the geometric region. This is the regime typically studied past works where the effects of the underlying metric space are strong and where clustering remains finite in the thermodynamic limit. Motivated by these results for single-layer graphs we also study geometric multiplexes. We introduce the mutual network, which is made up of all edges that are shared by all layers. This object allows us to obtain rigorous results on edge overlap as well as mutual clustering. We show that the geometric region can be extended in the mutual case when the coupling of the individual layers to their underlying metric space are of similar strengths. Having extensively investigated the structural properties at various coupling strengths, we lastly turn to dynamical processes running of top of the network. Specifically, we show that the underlying metric space reveals periodic Turing patterns, both in the quasi- and strongly geometric regimes as well as in empirical networks. All these results show that the underlying geometry is essential for understanding complex networks, both from a structural as well as dynamical point of view.
publishDate 2024
dc.date.none.fl_str_mv 2024
dc.type.none.fl_str_mv info:eu-repo/semantics/doctoralThesis
info:eu-repo/semantics/publishedVersion
format doctoralThesis
status_str publishedVersion
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/218518
http://hdl.handle.net/10803/693572
url https://hdl.handle.net/2445/218518
http://hdl.handle.net/10803/693572
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.rights.none.fl_str_mv cc by-nc-sa (c) Kolk, Jasper Eibertus van der, 2025
http://creativecommons.org/licenses/by-nc-sa/3.0/es/
info:eu-repo/semantics/openAccess
rights_invalid_str_mv cc by-nc-sa (c) Kolk, Jasper Eibertus van der, 2025
http://creativecommons.org/licenses/by-nc-sa/3.0/es/
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Universitat de Barcelona
publisher.none.fl_str_mv Universitat de Barcelona
dc.source.none.fl_str_mv Tesis Doctorals - Facultat - Física
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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spelling The Onset of Geometry in Complex Networks - From Stuctural Properties to Dynamical ProcessesKolk, Jasper Eibertus van derSistemes complexosGeometriaXarxes (Matemàtica)Complex systemsGeometryNets (Mathematics)[eng] Over the past few decades, the use of complex networks to describe the properties of systems of many interacting particles has become widespread in many fields of science. Surprisingly, networks from disparate disciplines share a wide range of basic properties, such as small worldness, high levels of clustering and broad degree distributions. One of the most promising frameworks to explain this observation is that of network geometry, where nodes are assumed to live in some underlying metric space that conditions their connectivity. The fact that this approach can reproduce all the basic network properties and symmetries as well as produce strong results in practical tasks such as community detection and link prediction has led many to wonder if there is a way to determine if real networks are indeed geometric in nature. However, these studies do not contemplate the fact that the transition between non-geometric and geometric networks might not be sharp. In this thesis we study the effect the effect of the underlying metric space on the complex network for different geometric coupling strengths. We show that three different regimes can be identified: In the non-geometric regime, where the coupling is extremely weak, results are similar to those of the configuration model, which is explicitly non-geometric. Increasing the coupling slightly leads us to the quasi-geometric regime, where the scaling of the clustering coefficient with the system size is extremely slow, leading to significant levels of this quantity for finite systems. Additionally, we show that, here, geometric information can be extracted from the topology alone through network embedding, and that it is essential for obtaining self-similar network replicas through geometric renormalization. Finally, we study a large number of empirical networks and show that they are best described in the quasi-geometric regime. Increasing the coupling further leads us the geometric region. This is the regime typically studied past works where the effects of the underlying metric space are strong and where clustering remains finite in the thermodynamic limit. Motivated by these results for single-layer graphs we also study geometric multiplexes. We introduce the mutual network, which is made up of all edges that are shared by all layers. This object allows us to obtain rigorous results on edge overlap as well as mutual clustering. We show that the geometric region can be extended in the mutual case when the coupling of the individual layers to their underlying metric space are of similar strengths. Having extensively investigated the structural properties at various coupling strengths, we lastly turn to dynamical processes running of top of the network. Specifically, we show that the underlying metric space reveals periodic Turing patterns, both in the quasi- and strongly geometric regimes as well as in empirical networks. All these results show that the underlying geometry is essential for understanding complex networks, both from a structural as well as dynamical point of view.[cat] En les darreres dècades, l'ús de xarxes complexes per descriure les propietats de sistemes amb moltes parts que interactuen ha esdevingut habitual en molts camps de la ciència. Sorprenentment, xarxes de disciplines diverses comparteixen una àmplia gamma de propietats bàsiques, com ara la propietat “small world”, alts nivells d’agrupació i distribucions de grau amplis. Un dels marcs més prometedors per explicar aquesta observació és el de la geometria de xarxes, on es presumeix que els nodes es troben en un espai mètric subjacent que condiciona la seva connectivitat. En aquesta tesi estudiem l'efecte de l'espai mètric subjacent en xarxes complexes per diferents intensitats de l'acoblament geomètric. Identifiquem tres règims diferents: En el règim no geomètric, on l'acoblament és extremadament feble, els resultats són similars als de models explícitament no geomètrics. Un augment lleuger de l'acoblament ens porta al règim quasi-geomètric, on l'escalat del coeficient d’agrupació amb la mida del sistema és molt lent, cosa que genera nivells significatius d'aquesta quantitat per a sistemes finits. A més, mostrem que, aquí, es pot extreure informació geomètrica només de la topologia mitjançant encaix de xarxes, i que és essencial per obtenir rèpliques auto-similars de xarxes mitjançant la renormalització geomètrica. Finalment, estudiem un gran nombre de xarxes empíriques i mostrem que es descriuen millor en el règim quasi-geomètric. Augmentar encara més l'acoblament ens condueix al règim geomètric. Aquest és el règim típicament estudiat en treballs anteriors, on l'agrupació es manté finita en el límit termodinàmic. Motivats per aquests resultats per a grafs monocapa, també estudiem multiplexes geomètriques. Introduïm la xarxa mútua, formada per totes les arestes compartides per totes les capes, i obtenim resultats rigorosos sobre la superposició d’arestes i triangles. Després d'investigar les propietats estructurals a diferents intensitats d'acoblament, ens centrem en els processos dinàmics a la xarxa. Mostrem que l'espai mètric subjacent revela patrons periòdics de Turing, tant en règims quasi-geomètrics i fortament geomètrics com en xarxes empíriques. Aquests resultats mostren que la geometria subjacent és essencial per entendre les xarxes complexes, tant des d'un punt de vista estructural com dinàmic.Universitat de BarcelonaBoguñá, MariánSerrano Moral, Ma. Ángeles (María Ángeles)Universitat de Barcelona. Facultat de Física2024info:eu-repo/semantics/doctoralThesisinfo:eu-repo/semantics/publishedVersionapplication/pdfhttps://hdl.handle.net/2445/218518http://hdl.handle.net/10803/693572Tesis Doctorals - Facultat - Físicareponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaIngléscc by-nc-sa (c) Kolk, Jasper Eibertus van der, 2025http://creativecommons.org/licenses/by-nc-sa/3.0/es/info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/2185182026-05-27T06:46:51Z
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