Effects of Empty Sites on Cooperation in the Prisoner’s Dilemma Game Based on Social Diversity

Figure 1

Relative density of cooperators 𝜌_𝑐/𝜌 as a function of temptation to defection 𝑏 for different values of 𝜌 when 𝜇=0.5 and 𝛼=3 (see legend). For 𝜌=0.9 or 0.8, the cooperation level is profoundly enhanced for a wide range of values of 𝑏. However, the cooperation level is deteriorated for smaller values of 𝜌, for example, 𝜌=0.7. When 𝜌=0.4, relative density of cooperators 𝜌_𝑐/𝜌 decreases monotonically and slightly with the increase of 𝑏.