Abstract
I will showcase a recent work in this talk. We study the following classical bilateral trade model: A seller with a private cost is selling one item to a buyer with a private value, where the cost and the value are drawn from publicly known independent distributions. The celebrated result of Myerson and Satterthwaite in 1983 states that in general, no incentive-compatible, individually rational and weakly budget balanced mechanism can be socially efficient. Given this, a natural question is whether there exists a mechanism with these properties that guarantees a constant fraction of the first-best gains-from-trade, a natural benchmark measuring the level of maximum possible efficiency when the agents are not strategic. We positively resolve this long-standing open question using a simple mechanism. This is based on joint work with Yuan Deng, Jieming Mao and Balasubramanian Sivan from Google Research.