Inhomogeneous random graphs with infinite-mean fitness variables

Fuente: arXiv
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Autores principales: Avena, Luca, Garlaschelli, Diego, Hazra, Rajat Subhra, Lalli, Margherita
Formato: Preprint
Publicado: 2022
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author Avena, Luca
Garlaschelli, Diego
Hazra, Rajat Subhra
Lalli, Margherita
author_facet Avena, Luca
Garlaschelli, Diego
Hazra, Rajat Subhra
Lalli, Margherita
contents We consider an inhomogeneous Erdős-Rényi random graph ensemble with exponentially decaying random disconnection probabilities determined by an i.i.d. field of variables with heavy tails and infinite mean associated to the vertices of the graph. This model was recently investigated in the physics literature in Garuccio et al. (2020) as a scale-invariant random graph within the context of network renormalization. From a mathematical perspective, the model fits in the class of scale-free inhomogeneous random graphs whose asymptotic geometrical features have been recently attracting interest. While for this type of graphs several results are known when the underlying vertex variables have finite mean and variance, here instead we consider the case of one-sided stable variables with necessarily infinite mean. To simplify our analysis, we assume that the variables are sampled from a Pareto distribution with parameter $α\in(0,1)$. We start by characterizing the asymptotic distributions of the typical degrees and some related observables. In particular, we show that the degree of a vertex converges in distribution, after proper scaling, to a mixed Poisson law. We then show that correlations among degrees of different vertices are asymptotically non-vanishing, but at the same time a form of asymptotic tail independence is found when looking at the behavior of the joint Laplace transform around zero. Moreover, we present some findings concerning the asymptotic density of wedges and triangles and show a cross-over for the existence of dust (i.e. disconnected vertices).
format Preprint
id arxiv_https___arxiv_org_abs_2212_08462
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Inhomogeneous random graphs with infinite-mean fitness variables
Avena, Luca
Garlaschelli, Diego
Hazra, Rajat Subhra
Lalli, Margherita
Probability
Disordered Systems and Neural Networks
Statistical Mechanics
Data Analysis, Statistics and Probability
We consider an inhomogeneous Erdős-Rényi random graph ensemble with exponentially decaying random disconnection probabilities determined by an i.i.d. field of variables with heavy tails and infinite mean associated to the vertices of the graph. This model was recently investigated in the physics literature in Garuccio et al. (2020) as a scale-invariant random graph within the context of network renormalization. From a mathematical perspective, the model fits in the class of scale-free inhomogeneous random graphs whose asymptotic geometrical features have been recently attracting interest. While for this type of graphs several results are known when the underlying vertex variables have finite mean and variance, here instead we consider the case of one-sided stable variables with necessarily infinite mean. To simplify our analysis, we assume that the variables are sampled from a Pareto distribution with parameter $α\in(0,1)$. We start by characterizing the asymptotic distributions of the typical degrees and some related observables. In particular, we show that the degree of a vertex converges in distribution, after proper scaling, to a mixed Poisson law. We then show that correlations among degrees of different vertices are asymptotically non-vanishing, but at the same time a form of asymptotic tail independence is found when looking at the behavior of the joint Laplace transform around zero. Moreover, we present some findings concerning the asymptotic density of wedges and triangles and show a cross-over for the existence of dust (i.e. disconnected vertices).
title Inhomogeneous random graphs with infinite-mean fitness variables
topic Probability
Disordered Systems and Neural Networks
Statistical Mechanics
Data Analysis, Statistics and Probability
url https://arxiv.org/abs/2212.08462