Sequential auctions and externalities
Sequential auctions and externalities
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顺序拍卖和外部性
DOI：
10.1137/1.9781611973099.70
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发表时间：
2011
影响因子：
0.5
通讯作者：
É. Tardos
中科院分区：
文献类型：
--
作者：
R. Leme;Vasilis Syrgkanis;É. Tardos
在许多情况下，代理人参与多个不同的拍卖，这些拍卖不一定同时进行。未来的机会会影响每次拍卖中参与者的战略考虑，从而引入外部性。出于这种考虑，我们研究了买方和卖方市场的设置，其中每个卖方持有一件物品，投标人进行组合估价，卖方依次举行物品拍卖。
我们的结果与同时拍卖的结果有质的不同，证明同时性是以前工作的一个重要方面。我们证明，如果卖方连续进行第一价格拍卖，那么对于单位需求投标人（匹配市场），每个子博弈完美均衡都实现至少一半的最优社会福利，而对于子模块投标人或使用第二价格拍卖时，社会福利可能比最优社会福利任意差。我们还表明，购买或出售拟阵基的首次价格顺序拍卖始终是有效的，并且实现了 VCG 结果。
我们分析中的一个重要工具是研究具有外部性的第一和第二价格拍卖（投标人对每个可能的获胜者结果进行估值），这可能具有独立的利益。我们证明，纯纳什均衡始终存在于具有外部性的第一价格拍卖中。
In many settings agents participate in multiple different auctions that are not necessarily implemented simultaneously. Future opportunities affect strategic considerations of the players in each auction, introducing externalities. Motivated by this consideration, we study a setting of a market of buyers and sellers, where each seller holds one item, bidders have combinatorial valuations and sellers hold item auctions sequentially.
Our results are qualitatively different from those of simultaneous auctions, proving that simultaneity is a crucial aspect of previous work. We prove that if sellers hold sequential first price auctions then for unit-demand bidders (matching market) every subgame perfect equilibrium achieves at least half of the optimal social welfare, while for submodular bidders or when second price auctions are used, the social welfare can be arbitrarily worse than the optimal. We also show that a first price sequential auction for buying or selling a base of a matroid is always efficient, and implements the VCG outcome.
An important tool in our analysis is studying first and second price auctions with externalities (bidders have valuations for each possible winner outcome), which can be of independent interest. We show that a Pure Nash Equilibrium always exists in a first price auction with externalities.