  In our multi-agent model agents generate wealth from repeated interactions
for which a prisoner's dilemma payoff matrix is assumed. Their gains are taxed
by a government at a rate $\alpha$. The resulting budget is spent to cover
administrative costs and to pay a bonus to cooperative agents, which can be
identified correctly only with a probability $p$. Agents decide at each time
step to choose either cooperation or defection based on different information.
In the local scenario, they compare their potential gains from both strategies.
In the global scenario, they compare the gains of the cooperative and defective
subpopulations. We derive analytical expressions for the critical bonus needed
to make cooperation as attractive as defection. We show that for the local
scenario the government can establish only a medium level of cooperation,
because the critical bonus increases with the level of cooperation. In the
global scenario instead full cooperation can be achieved once the cold-start
problem is solved, because the critical bonus decreases with the level of
cooperation. This allows to lower the tax rate, while maintaining high
cooperation.
