của mô hình trong mục , trong đó sự chậm trễ trước khi bên bán có thể cung cấp cho người mua mới có thể khác nhau từ sự chậm trễ giữa bất kỳ hai giai đoạn kế tiếp của thương lượng. (Xem Muthoo (1993).) Lắc và Sutton sử dụng mô hình của họ, trong đó một giá rẻ công ty với hai công nhân, | 166 Chapter 8. A Market with One-Time Entry Figure A vector z for which VK c t uK c z and pz 0. k K. By the strict concavity of uk and Jensen s inequality we have Vk wfe 0 E uk yk uk E yk where E is the expectation operator with strict inequality unless yk is degenerate. Let yk E yk . Hence uk yk maxx Xfc uk x px p k with strict inequality for k K. Therefore pyk p k for all k and pyK pZk. Thus p K 1 nkyk p ZK 1 nk k contradicting the condition K 1 nkyk zf i nk k for y1 . yK to be an allocation. Note that Assumption 2 p. 158 is used in Step 7. It is used to show that if pz 0 then there is a trade in the direction z that makes any agent who is ready to leave the market better off. Thus by executing a sequence of such trades an agent who holds the bundle c is assured of eventually obtaining the bundle c z. Suppose the agents preferences do not satisfy Assumption 2. Then the curvature of the agents indifference curves at the bundles with which they exit from the market in period t might increase with t in such a way that the exiting agents are willing to accept only a Characterization of Market Equilibrium 167 sequence of successively smaller trades in the direction z a sequence that never adds up to z itself. Two arguments are central to the proof. First the allocation associated with the bundles with which agents exit is efficient Step 6 . The idea is that if there remain feasible trades between the members of two sets of agents that make the members of both sets better off then by waiting sufficiently long each member of one set is sure of meeting a member of the other set in which case a mutually beneficial trade can take place. Three assumptions are important here. First no agent is impatient. Every agent is willing to wait as long as necessary to execute a trade. Second the matching technology has the property that if in some period there is a positive measure of agents of type k holding the bundle c then in every future period there will be a positive .
