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Main Authors: Berestycki, Henri, Novikov, Alexei, Roquejoffre, Jean-Michel, Ryzhik, Lenya
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2409.11479
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author Berestycki, Henri
Novikov, Alexei
Roquejoffre, Jean-Michel
Ryzhik, Lenya
author_facet Berestycki, Henri
Novikov, Alexei
Roquejoffre, Jean-Michel
Ryzhik, Lenya
contents The Lucas-Moll system is a mean-field game type model describing the growth of an economy by means of diffusion of knowledge. The individual agents in the economy advance their knowledge by learning from each other and via internal innovation. Their cumulative distribution function satisfies a forward in time nonlinear non-local reaction-diffusion type equation. On the other hand, the learning strategy of the agents is based on the solution to a backward in time nonlocal Hamilton-Jacobi-Bellman equation that is coupled to the aforementioned equation for the agents density. Together, these equations form a system of the mean-field game type. When the learning rate is sufficiently large, existence of balanced growth path solutions to the Lucas-Moll system was proved in~\cite{PRV,Porretta-Rossi}. Here, we analyze a complementary regime where the balanced growth paths do not exist. The main result is a long time convergence theorem. Namely, the solution to the initial-terminal value problem behaves in such a way that at large times an overwhelming majority of the agents spend no time producing at all and are only learning. In particular, the agents density propagates at the Fisher-KPP speed. We name this type of solutions a lottery society.
format Preprint
id arxiv_https___arxiv_org_abs_2409_11479
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Diffusion of knowledge and the lottery society
Berestycki, Henri
Novikov, Alexei
Roquejoffre, Jean-Michel
Ryzhik, Lenya
Analysis of PDEs
Probability
The Lucas-Moll system is a mean-field game type model describing the growth of an economy by means of diffusion of knowledge. The individual agents in the economy advance their knowledge by learning from each other and via internal innovation. Their cumulative distribution function satisfies a forward in time nonlinear non-local reaction-diffusion type equation. On the other hand, the learning strategy of the agents is based on the solution to a backward in time nonlocal Hamilton-Jacobi-Bellman equation that is coupled to the aforementioned equation for the agents density. Together, these equations form a system of the mean-field game type. When the learning rate is sufficiently large, existence of balanced growth path solutions to the Lucas-Moll system was proved in~\cite{PRV,Porretta-Rossi}. Here, we analyze a complementary regime where the balanced growth paths do not exist. The main result is a long time convergence theorem. Namely, the solution to the initial-terminal value problem behaves in such a way that at large times an overwhelming majority of the agents spend no time producing at all and are only learning. In particular, the agents density propagates at the Fisher-KPP speed. We name this type of solutions a lottery society.
title Diffusion of knowledge and the lottery society
topic Analysis of PDEs
Probability
url https://arxiv.org/abs/2409.11479