抄録
Since the analysis by Olson (1965), several articles have been devoted to the study of voluntary contribution to public goods, using various models. Especially, Palfrey and Rothenthal (1984) and Gradstein and Nitzan (1990) analyze binary contribution models assuming that communities are homogeneous. In their model, each player chooses whether to contribute to the public good or not. Gradstein and Nitzan (1990) show that the player with low cost is more likely to contribute if the community is homogeneous.
They consider only homogeneous communities. So we cannot understand what type of agent more willingly contribute. In this paper, we study this problem, considering heterogeneous communities. That is, we analyze the relation between each player's willingness to contribute and his or her cost of contribution.
In this paper, we assume that there are two types of agents in a community. One type is an agent with low cost and the other type is agent with high cost. We focus on the Nash equilibrium with symmetric mixed strategy. There are possibly some Nash equilibria with symmetric mixed strategy. In this paper, we prove that there is the Nash equilibrium with symmetric mixed strategy such that the agent with high cost more willingly contributes.
