Efficient Actions in a Dynamic Auction Environment
研究了竞拍者私人价值随时间变化（因私人行动或外生冲击）时的有效拍卖机制，发现无完全承诺时，为有效进入需付出昂贵信号成本，并提出了一个近乎有效且能协调分离均衡的简单机制。
We model an environment, where bidders’ private values may change over time as a result of both costly private actions and exogenous shocks. Examples of private actions include investment and entry decisions; shocks might be due to exogenous changes in a potential buyer’s circumstances. We describe an efficient auction mechanism that maximizes the final value of the object to the winning bidder net of the total cost of investment by all agents. In particular, we show that, assuming that the auctioneer does not have full commitment power, costly signalling is necessary for efficient entry when agents receive private information both before and after they make the entry decision. To rule out pooling equilibria that coexist with the efficient equilibrium in the basic mechanism, we introduce a virtual-implementation-style mechanism that (i) is almost efficient; (ii) forces players to coordinate on the separating equilibrium; and (iii) is simple enough to be potentially useful in practice.