Spatial snowdrift game in heterogeneous agent systems with co-evolutionary strategies and updating rules*
Xia Hai-Jiang, Li Ping-Ping, Ke Jian-Hong†, Lin Zhen-Quan
       
The equilibrium cooperation frequency f c as a function of the cost-to-benefit ratio r at ν T = 3. It is shown that f c always exhibits a discontinuous steplike structure for an arbitrary composition f a 0, and the value of f c is dependent on f a 0 only in the range of 0 < r < 1/4.