Fig. 7: The impact of the single port fee difference policy on the evolutionary strategies of the parties.

a The impact of the single port fee difference policy on the evolution process; b the impact of the single port fee difference policy on the probability of x making a decision over time; c the impact of the single port fee difference on the probability of y making a decision over time; d the impact of the single port fee difference policy on the probability of z making a decision over time.