日時：2019年 7月 16日（火）16:30-18:00
場所：3F1200L (3F棟12階）
講演者：図斎　大 氏（Temple University）
司会者：澤亮治

Title: Gains in evolutionary dynamics: a unifying approach to dynamic 
stability of contractive games and ESS

Abstract:
In this paper, we investigate gains from strategy revisions in 
deterministic evolutionary dynamics. To clarify the gain from revision, 
we propose a framework to reconstruct an evolutionary dynamic from 
optimal decision with stochastic (possibly restricted) available action 
set and switching cost. Many of major dynamics can be constructed in 
this framework. We formally define net gains from revisions and obtain 
several general properties of the gain function, which leads to Nash 
stability of contractive games—generalization of concave potential 
games—and local asymptotic stability of a (regular) evolutionary stable 
state. The unifying framework allows us to apply the Nash stability to 
mixture of heterogeneous populations, whether heterogeneity is 
observable or unobservable or whether heterogeneity is in payoffs or in 
revision protocols. This extends the known positive results on 
evolutionary implementation of social optimum through Pigouvian pricing 
to the presence of heterogeneity and non-aggregate payoff perturbations. 
While the analysis here is confined to general strategic-form games, we 
finally discuss that the idea of reconstructing evolutionary dynamics 
from optimization with switching costs and focusing on net revision 
gains for stability is promising for further applications to more 
complex situations.

The presenter's website:
https://sites.temple.edu/zusai/