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 frequency g cb versus the cost-to-benefit ratio r versus the upper limit of tolerance ν T for different f a 0 is plotted as a contour map. Here, (a) f a 0 = 0; (b) f a 0 = 0.3; (c) f a 0 = 0.5; (d) f a 0 = 0.8; and (e) f a 0 = 1.0. It is shown that g cb equals zero for almost all experimental parameters, except for large ν T and small r .