NFO13018901 Intro Network science14307130355李婧雅 FIG. 7The cluster graph and p curve when T=1.9(P50=0.3402) 80100120140160180200 FIG 8 The cluster graph and p curve when T=2(Ps0=0.0441) 4.1.2 analysis From the result we can get three conclusions A. When T=1.3, the network still has high cooperator density but when t=1. 6 and 1.9 there is a rapid fall of cooperator density and when T=2, p is nearly 0 which means almost all players choose to defect. So we know T=2 is about the threshold value of disappearance of cooperatorsINFO130189.01 Intro Network Science 14307130355 李婧雅 12 FIG. 7 The cluster graph and  curve when T=1.9( 50 =0.3402) FIG. 8 The cluster graph and  curve when T=2( 50 =0.0441) 4.1.2 analysis From the result we can get three conclusions: A. When T=1.3, the network still has high cooperator density but when T=1.6 and 1.9, there is a rapid fall of cooperator density and when T=2,  is nearly 0 which means almost all players choose to defect. So we know T=2 is about the threshold value of disappearance of cooperators