Analysis of the expected density of internal equilibria in random evolutionary multi-player multi-strategy games

TL;DR

This paper investigates the distribution and expected number of internal equilibria in random multi-player, multi-strategy evolutionary games, revealing asymptotic behaviors and connections to random polynomial theory.

Contribution

It provides new qualitative and quantitative results on the expected density and number of internal equilibria, including asymptotic behavior and monotonicity in multi-player two-strategy games.

Findings

Expected density and number of equilibria grow as rom simulations.

Asymptotic behavior of or large d in two-strategy games.

Numerical support for conjectures in multi-strategy cases.

Abstract

In this paper, we study the distribution and behaviour of internal equilibria in a $d$-player $n$-strategy random evolutionary game where the game payoff matrix is generated from normal distributions. The study of this paper reveals and exploits interesting connections between evolutionary game theory and random polynomial theory. The main novelties of the paper are some qualitative and quantitative results on the expected density, $f_{n,d}$, and the expected number, $E(n,d)$, of (stable) internal equilibria. Firstly, we show that in multi-player two-strategy games, they behave asymptotically as $\sqrt{d-1}$ as $d$ is sufficiently large. Secondly, we prove that they are monotone functions of $d$. We also make a conjecture for games with more than two strategies. Thirdly, we provide numerical simulations for our analytical results and to support the conjecture. As consequences of our analysis, some qualitative and quantitative results on the distribution of zeros of a random Bernstein polynomial are also obtained.