We study revenue maximization in multi-item auctions, where bidders have subadditive valuations over independent items. Providing a simple mechanism that is approximately revenue-optimal in this setting is a major open problem in mechanism design. In this paper, we present the first \emph{simple mechanism} whose revenue is at least a \emph{constant fraction} of the optimal revenue in multi-item auctions with subadditive bidders. Our mechanism is a simultaneous auction that incorporates either a personalized entry fee or a personalized reserve price per item. We prove that for any simultaneous auction that satisfies c-efficiency -- a new property we propose, its revenue is at least an $O(c)$-approximation to the optimal revenue. We further show that both the \emph{simultaneous first-price} and the \emph{simultaneous all-pay auction} are $1\over 2$-efficient. Providing revenue guarantees for non-truthful simple mechanisms, e.g., simultaneous auctions, in multi-dimensional environments has been recognized by Roughgarden et al. as an important open question. Prior to our result, the only such revenue guarantees are due to Daskalakis et al. for bidders who have additive valuations over independent items. Our result significantly extends the revenue guarantees of these non-truthful simple auctions to settings where bidders have combinatorial valuations.

翻译：我们研究了多物品拍卖中的收益最大化问题，其中竞拍者对独立物品具有次可加估值。在此设定下提供一种近似收益最优的简单机制是机制设计中的一个重大开放问题。本文提出了首个收益至少为多物品拍卖（含次可加竞拍者）最优收益常数的简单机制。我们的机制是一种同时拍卖，它融合了个性化入场费或每件物品的个性化保留价。我们证明了任何满足我们提出的新性质c-效率的同时拍卖，其收益至少是最优收益的O(c)近似。我们进一步表明，同时一价拍卖和同时全支付拍卖均为1/2效率。为非诚实简单机制（如同时拍卖）提供收益保证，在多维环境中已被Roughgarden等人认定为重要开放问题。在我们结果之前，仅Daskalakis等人为对独立物品具有加性估值的竞拍者提供了此类收益保证。我们的结果将这些非诚实简单拍卖的收益保证显著扩展到竞拍者具有组合估值的场景。