Continuum and thermodynamic limits for a simple random-exchange model

Fuente: arXiv
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Hauptverfasser: Düring, Bertram, Georgiou, Nicos, Merino-Aceituno, Sara, Scalas, Enrico
Format: Preprint
Veröffentlicht: 2020
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_version_ 1866913278527012864
author Düring, Bertram
Georgiou, Nicos
Merino-Aceituno, Sara
Scalas, Enrico
author_facet Düring, Bertram
Georgiou, Nicos
Merino-Aceituno, Sara
Scalas, Enrico
contents We discuss various limits of a simple random exchange model that can be used for the distribution of wealth. We start from a discrete state space - discrete time version of this model and, under suitable scaling, we show its functional convergence to a continuous space - discrete time model. Then, we show a thermodynamic limit of the empirical distribution to the solution of a kinetic equation of Boltzmann type. We solve this equation and we show that the solutions coincide with the appropriate limits of the invariant measure for the Markov chain. In this way we complete Boltzmann's program of deriving kinetic equations from random dynamics for this simple model. Three families of invariant measures for the mean field limit are discovered and we show that only two of those families can be obtained as limits of the discrete system and the third is extraneous. Finally, we cast our results in the framework of integer partitions and strengthen some results already available in the literature.
format Preprint
id arxiv_https___arxiv_org_abs_2003_00930
institution arXiv
publishDate 2020
record_format arxiv
spellingShingle Continuum and thermodynamic limits for a simple random-exchange model
Düring, Bertram
Georgiou, Nicos
Merino-Aceituno, Sara
Scalas, Enrico
Probability
General Economics
Economics
60J05, 60F17, 35Q91, 35Q20, 60J10, 60J20, 82B31, 82B40
We discuss various limits of a simple random exchange model that can be used for the distribution of wealth. We start from a discrete state space - discrete time version of this model and, under suitable scaling, we show its functional convergence to a continuous space - discrete time model. Then, we show a thermodynamic limit of the empirical distribution to the solution of a kinetic equation of Boltzmann type. We solve this equation and we show that the solutions coincide with the appropriate limits of the invariant measure for the Markov chain. In this way we complete Boltzmann's program of deriving kinetic equations from random dynamics for this simple model. Three families of invariant measures for the mean field limit are discovered and we show that only two of those families can be obtained as limits of the discrete system and the third is extraneous. Finally, we cast our results in the framework of integer partitions and strengthen some results already available in the literature.
title Continuum and thermodynamic limits for a simple random-exchange model
topic Probability
General Economics
Economics
60J05, 60F17, 35Q91, 35Q20, 60J10, 60J20, 82B31, 82B40
url https://arxiv.org/abs/2003.00930