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Infection Spread in Random Geometric Graphs

Part of: Distribution theory Combinatorial probability Markov processes Special processes

Published online by Cambridge University Press:  04 January 2016

Ghurumuruhan Ganesan
Ghurumuruhan Ganesan*
Affiliation:
École Polytechnique Fédérale de Lausanne
*
∗ Postal address: MA B1 527, École Polytechnique Fédérale de Lausanne, Station 8, CH-1015 Lausanne, Switzerland. Email address: gganesan82@gmail.com
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Abstract

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In this paper we study the speed of infection spread and the survival of the contact process in the random geometric graph G = G(n, rn, f) of n nodes independently distributed in S = [-½, ½]2 according to a certain density f(·). In the first part of the paper we assume that infection spreads from one node to another at unit rate and that infected nodes stay in the same state forever. We provide an explicit lower bound on the speed of infection spread and prove that infection spreads in G with speed at least D1nrn2. In the second part of the paper we consider the contact process ξt on G where infection spreads at rate λ > 0 from one node to another and each node independently recovers at unit rate. We prove that, for every λ > 0, with high probability, the contact process on G survives for an exponentially long time; there exist positive constants c1 and c2 such that, with probability at least 1 - c1 / n4, the contact process starting with all nodes infected survives up to time tn = exp(c2n/logn) for all n.

Keywords

Random geometric graphspeed of infection spreadsurvival time of contact process

MSC classification

Primary: 60J10: Markov chains (discrete-time Markov processes on discrete state spaces) 60K35: Interacting random processes; statistical mechanics type models; percolation theory
Secondary: 60C05: Combinatorial probability 62E10: Characterization and structure theory
Type
General Applied Probability
Information
Advances in Applied Probability , Volume 47 , Issue 1 , March 2015 , pp. 164 - 181
Copyright
© Applied Probability Trust 

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