微笑向暖普林斯顿大学博弈论讲义3-10
3,3r 12,2d 1a 1
r 2D A 1,1r 1d 2a 20,0
Figure 1:A perfect-information game
Strategies and normal form(s)
De?nition 1is arguably a “natural”way of describing a dynamic game—and one that is at least implicit in most applications of the theory.
According to our formulations,actions are the primitive objects of choice.However,the notion of a strategy ,i.e.a history-contingent plan,is also relevant:
De?nition 2Fix an extensive-form game with perfect information Γ.For every history h ∈X ,let A (h )={a ∈A :(h,a )∈H }be the set of actions available at h .Then,for every player i ∈N ,a strategy is a function s i :P ?1(i )→A such that,for every h such that P (h )=i ,s i (h )∈A (h ).Denote by S i and S the set of strategies of Player i and the set of all strategy pro?les.
