The projection method: a unified formalism for community detection

We present the class of projection methods for community detection that generalizes many popular community detection methods. In this framework, we represent each clustering (partition) by a vector on a high-dimensional hypersphere. A community detection method is a projection method if it can be de...

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Main Authors: Martijn Gösgens, Remco van der Hofstad, Nelly Litvak
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-02-01
Series:Frontiers in Complex Systems
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fcpxs.2024.1331320/full
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author Martijn Gösgens
Remco van der Hofstad
Nelly Litvak
author_facet Martijn Gösgens
Remco van der Hofstad
Nelly Litvak
author_sort Martijn Gösgens
collection DOAJ
description We present the class of projection methods for community detection that generalizes many popular community detection methods. In this framework, we represent each clustering (partition) by a vector on a high-dimensional hypersphere. A community detection method is a projection method if it can be described by the following two-step approach: 1) the graph is mapped to a query vector on the hypersphere; and 2) the query vector is projected on the set of clustering vectors. This last projection step is performed by minimizing the distance between the query vector and the clustering vector, over the set of clusterings. We prove that optimizing Markov stability, modularity, the likelihood of planted partition models and correlation clustering fit this framework. A consequence of this equivalence is that algorithms for each of these methods can be modified to perform the projection step in our framework. In addition, we show that these different methods suffer from the same granularity problem: they have parameters that control the granularity of the resulting clustering, but choosing these to obtain clusterings of the desired granularity is nontrivial. We provide a general heuristic to address this granularity problem, which can be applied to any projection method. Finally, we show how, given a generator of graphs with community structure, we can optimize a projection method for this generator in order to obtain a community detection method that performs well on this generator.
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spelling doaj.art-675c67bcb3f241f984d0b92d9d8217c62024-02-26T04:52:07ZengFrontiers Media S.A.Frontiers in Complex Systems2813-61872024-02-01210.3389/fcpxs.2024.13313201331320The projection method: a unified formalism for community detectionMartijn GösgensRemco van der HofstadNelly LitvakWe present the class of projection methods for community detection that generalizes many popular community detection methods. In this framework, we represent each clustering (partition) by a vector on a high-dimensional hypersphere. A community detection method is a projection method if it can be described by the following two-step approach: 1) the graph is mapped to a query vector on the hypersphere; and 2) the query vector is projected on the set of clustering vectors. This last projection step is performed by minimizing the distance between the query vector and the clustering vector, over the set of clusterings. We prove that optimizing Markov stability, modularity, the likelihood of planted partition models and correlation clustering fit this framework. A consequence of this equivalence is that algorithms for each of these methods can be modified to perform the projection step in our framework. In addition, we show that these different methods suffer from the same granularity problem: they have parameters that control the granularity of the resulting clustering, but choosing these to obtain clusterings of the desired granularity is nontrivial. We provide a general heuristic to address this granularity problem, which can be applied to any projection method. Finally, we show how, given a generator of graphs with community structure, we can optimize a projection method for this generator in order to obtain a community detection method that performs well on this generator.https://www.frontiersin.org/articles/10.3389/fcpxs.2024.1331320/fullcommunity detectionclusteringmodularityMarkov stabilityCorrelation clusteringgranularity
spellingShingle Martijn Gösgens
Remco van der Hofstad
Nelly Litvak
The projection method: a unified formalism for community detection
Frontiers in Complex Systems
community detection
clustering
modularity
Markov stability
Correlation clustering
granularity
title The projection method: a unified formalism for community detection
title_full The projection method: a unified formalism for community detection
title_fullStr The projection method: a unified formalism for community detection
title_full_unstemmed The projection method: a unified formalism for community detection
title_short The projection method: a unified formalism for community detection
title_sort projection method a unified formalism for community detection
topic community detection
clustering
modularity
Markov stability
Correlation clustering
granularity
url https://www.frontiersin.org/articles/10.3389/fcpxs.2024.1331320/full
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