Strategic manipulation in a society with indivisible goods

The authors consider a problem of exchanging indivisible goods in a society, in which initially each agent has only one unit of indivisible goods respectively. Here they discuss the problem in the framework of social choice rule. For this problem, it is well known that Top Trading Cycle Procedure (TTC) leads to a solution in the core. When the preference profile of the agents are not known publicly, a new matter whether they will have an incentive to manipulate strategically in revealing their preference profile arises. It is shown that strategic manipulation by an agent is impossible in TCC. In this paper the authors further prove that strategic manipulation by any coalition is also impossible in TTC. First, they show that TTC can be regarded as a kind of social choice rule by modifying the preference domain of agents in TTC. Then the authors will prove the strategic non-manipulability by using theorems in the paper by Dasgupta, Hammond and Maskin. Finally, they compare this result with previous results in some existing literature on strategic manipulation. [In Japanese].