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Related papers: New bounds on the modularity of $G(n,p)$

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The modularity of a graph is a parameter that measures its community structure; the higher its value (between $0$ and $1$), the more clustered the graph is. In this paper we show that the modularity of a random $3$-regular graph is at least…

Probability · Mathematics 2023-07-24 Lyuben Lichev , Dieter Mitsche

This work will appear as a chapter in a forthcoming volume titled `Topics in Probabilistic Graph Theory'. For a given graph $G$, each partition of the vertices has a modularity score, with higher values indicating that the partition better…

Probability · Mathematics 2025-09-29 Colin McDiarmid , Fiona Skerman

For a given graph $G$, each partition of the vertices has a modularity score, with higher values indicating that the partition better captures community structure in $G$. The modularity $q^*(G)$ of the graph $G$ is defined to be the maximum…

Combinatorics · Mathematics 2022-12-22 Colin McDiarmid , Fiona Skerman

We prove new lower bounds on the modularity of graphs. Specifically, the modularity of a graph $G$ with average degree $\bar d$ is $\Omega(\bar{d}^{-1/2})$, under some mild assumptions on the degree sequence of $G$. The lower bound…

Combinatorics · Mathematics 2023-07-17 Vilhelm Agdur , Nina Kamčev , Fiona Skerman

A basic question in network community detection is how modular a given network is. This is usually addressed by evaluating the quality of partitions detected in the network. The Girvan-Newman (GN) modularity function is the standard way to…

Physics and Society · Physics 2022-05-25 Filipi N. Silva , Aiiad Albeshri , Vijey Thayananthan , Wadee Alhalabi , Santo Fortunato

Clustering algorithms for large networks typically use modularity values to test which partitions of the vertex set better represent structure in the data. The modularity of a graph is the maximum modularity of a partition. We consider the…

Combinatorics · Mathematics 2022-12-22 Colin McDiarmid , Fiona Skerman

Given a graph of interactions, a module (also called a community or cluster) is a subset of nodes whose fitness is a function of the statistical significance of the pairwise interactions of nodes in the module. The topic of this paper is a…

Physics and Society · Physics 2018-08-20 Bhaskar DasGupta , Devendra Desai

Modularity is a very widely used measure of the level of clustering or community structure in networks. Here we consider a recent generalisation of the definition of modularity to temporal graphs, whose edge-sets change over discrete…

Combinatorics · Mathematics 2025-07-24 Vilhelm Agdur , Jessica Enright , Laura Larios-Jones , Kitty Meeks , Fiona Skerman , Ella Yates

In this paper we discuss some problematic aspects of Newman's modularity function QN. Given a graph G, the modularity of G can be written as QN = Qf -Q0, where Qf is the intracluster edge fraction of G and Q0 is the expected intracluster…

Social and Information Networks · Computer Science 2013-02-28 Athanasios Kehagias , Leonidas Pitsoulis

Communities are clusters of nodes with a higher than average density of internal connections. Their detection is of great relevance to better understand the structure and hierarchies present in a network. Modularity has become a standard…

Physics and Society · Physics 2015-03-17 Filippo Radicchi , Andrea Lancichinetti , José J. Ramasco

Modularity was introduced by Newman and Girvan in 2004 and is used as a measure of community structure of networks represented by graphs. In our work we study modularity of the random intersection graph model first considered by Karo\'nski,…

Combinatorics · Mathematics 2025-02-11 Katarzyna Rybarczyk

We relate two important notions in graph theory: expanders which are highly connected graphs, and modularity a parameter of a graph that is primarily used in community detection. More precisely, we show that a graph having modularity…

Combinatorics · Mathematics 2023-12-13 Baptiste Louf , Colin McDiarmid , Fiona Skerman

Modularity is designed to measure the strength of division of a network into clusters (known also as communities). Networks with high modularity have dense connections between the vertices within clusters but sparse connections between…

Probability · Mathematics 2017-07-18 Liudmila Ostroumova Prokhorenkova , Pawel Pralat , Andrei Raigorodskii

We examine a community structure in random graphs of size $n$ and link probability $p/n$ determined with the Newman greedy optimization of modularity. Calculations show that for $p<1$ communities are nearly identical with clusters. For…

Statistical Mechanics · Physics 2015-06-18 Adam Lipowski , Dorota Lipowska

Modularity introduced by Newman and Girvan [Phys. Rev. E 69, 026113 (2004)] is a quality function for community detection. Numerous methods for modularity maximization have been developed so far. In 2007, Barber [Phys. Rev. E 76, 066102…

Social and Information Networks · Computer Science 2015-06-05 Atsushi Miyauchi , Noriyoshi Sukegawa

Modularity is a quantity which has been introduced in the context of complex networks in order to quantify how close a network is to an ideal modular network in which the nodes form small interconnected communities that are joined together…

Probability · Mathematics 2021-04-05 Jordan Chellig , Nikolaos Fountoulakis , Fiona Skerman

The maximum modularity of a graph is a parameter widely used to describe the level of clustering or community structure in a network. Determining the maximum modularity of a graph is known to be NP-complete in general, and in practice a…

Data Structures and Algorithms · Computer Science 2022-12-22 Kitty Meeks , Fiona Skerman

The overlap gap property (OGP) is a statement about the geometry of near-optimal solutions. Exhibiting OGP implies failure of a class of local algorithms; and has been observed to coincide with conjectured algorithmic limits in problems…

Let $G$ be a finite graph with minimum degree $r$. Form a random subgraph $G_p$ of $G$ by taking each edge of $G$ into $G_p$ independently and with probability $p$. We prove that for any constant $\epsilon>0$, if $p=\frac{1+\epsilon}{r}$,…

Combinatorics · Mathematics 2013-06-25 Alan Frieze , Michael Krivelevich

Let ccl(G) denote the order of the largest complete minor in a graph G (also called the contraction clique number) and let G(n,p) denote a random graph on n vertices with edge probability p. Bollobas, Catlin and Erdos asymptotically…

Combinatorics · Mathematics 2007-05-23 N. Fountoulakis , D. Kühn , D. Osthus
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