A large‐deviations principle for all the cluster sizes of a sparse Erdős–Rényi graph. Issue 4 (5th April 2021)

• Record Type: Journal Article
• Authors: Andreis, Luisa; König, Wolfgang; Patterson, Robert I. A.
• Is Part Of: Random structures & algorithms. Volume 59:Issue 4(2021)
• Page Start: 522
• Page End: 553
• Publication Date: 2021-04-05
• Subjects: component sizes -- empirical measure -- Erdős–Rényi random graph -- gelation -- large deviations -- multiplicative coalescent -- phase transition -- sizes; Random graphs -- Periodicals; Mathematical analysis -- Periodicals; 519
• DOI: 10.1002/rsa.21007
• Languages: English
• ISSNs: 1042-9832

Abstract

Abstract: Let 𝒢 ( N, 1 N t N ) be the Erdős–Rényi graph with connection probability 1 N t N ∼ t / N as N → ∞ for a fixed t ∈ (0, ∞ ). We derive a large‐deviations principle for the empirical measure of the sizes of all the connected components of 𝒢 ( N, 1 N t N ), registered according to microscopic sizes (i.e., of finite order), macroscopic ones (i.e., of order N ), and mesoscopic ones (everything in between). The rate function explicitly describes the microscopic and macroscopic components and the fraction of vertices in components of mesoscopic sizes. Moreover, it clearly captures the well known phase transition at t = 1 as part of a comprehensive picture. The proofs rely on elementary combinatorics and on known estimates and asymptotics for the probability that subgraphs are connected. We also draw conclusions for the strongly related model of the multiplicative coalescent, the Marcus–Lushnikov coagulation model with monodisperse initial condition, and its gelation phase transition.