Calculus of Variations and Geometric Measure Theory

L. Ambrosio - M. Fornasier - M. Morandotti - G. Savaré

Spatially Inhomogeneous Evolutionary Games

created by morandott on 10 May 2018
modified on 20 Nov 2020


Accepted Paper

Inserted: 10 may 2018
Last Updated: 20 nov 2020

Journal: CPAM
Year: 2018

ArXiv: 1805.04027 PDF


We introduce and study a mean-field model for a system of spatially distributed players interacting through an evolutionary game driven by a replicator dynamics. Strategies evolve by a replicator dynamics influenced by the position and the interaction between different players and return a feedback on the velocity field guiding their motion.

One of the main novelties of our approach concerns the description of the whole system, which can be represented by an evolving probability measure $\Sigma$ on an infinite dimensional state space (pairs $(x,\sigma)$ of position and distribution of strategies). We provide a Lagrangian and a Eulerian description of the evolution, and we prove their equivalence, together with existence, uniqueness, and stability of the solution. As a byproduct of the stability result, we also obtain convergence of the finite agents model to our mean-field formulation, when the number $N$ of the players goes to infinity, and the initial discrete distribution of positions and strategies converge. To this aim we develop some basic functional analytic tools to deal with interaction dynamics and continuity equations in Banach spaces, that could be of independent interest.

Keywords: evolutionary games of mean-field type, spatially inhomogeneous replicator dynamics, well-posedness of ODE, superposition principle, well-posedness of transport equations in separable Banach spaces