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 relative cooperation frequencies g ca and g cb versus the cost-to-benefit ratio r at ν T = 3. It is shown that both g ca and g cb have a discontinuous steplike structure for each initial composition f a 0. g ca decreases with increasing f a 0 while g cb increases with f a 0. And g ca always has a non-zero value for arbitrary r and f a 0, while g cb consistently equals zero in the range of 1/5 < r < 1.