迈向MEV市场中的去中心化搜索者竞争
Towards Decentralized Searcher Competition in MEV Markets
中文总结 AI 辅助
本文针对MEV市场的中心化问题，提出经入口过滤的Shapley上限拍卖机制，以提升搜索者竞争的公平性与去中心化，解决Sybil攻击及合谋等安全挑战。
中文摘要 AI 辅助
最大可提取价值（MEV）市场中的中心化是区块链系统的一个重大问题，因为经济权力的持续集中会削弱竞争、降低开放性，并破坏无许可协议的去中心化目标。尽管现有分析多聚焦于构建者、验证者和区块构建市场，本文从搜索者竞争的视角研究中心化问题。我们构建了一个异质性模型，其中搜索者在机会覆盖范围和执行效率上存在差异，并分析拍卖设计如何影响竞争同一MEV机会的搜索者之间的公平性、去中心化和安全性。为评估搜索者竞争，我们引入两个指标：一是Shapley加权Jain公平指数，用于衡量奖励是否与搜索者的边际贡献成比例；二是预期奖励赫芬达尔-赫希曼指数（HHI），用于衡量长期搜索者奖励的集中度。利用这些指标，我们首先将标准的第一价格赢家通吃拍卖作为基准进行分析。分析表明，在搜索者异质性下，第一价格竞争可能奖励排名主导地位而非边际贡献，导致奖励集中，贡献调整后的公平性更弱。受这些局限的启发，我们提出一种经入口过滤的Shapley上限拍卖机制，该机制能在被接纳的高质量提交中更公平、更广泛地分配搜索者奖励。在无许可区块链环境中设计此类机制具有挑战性：搜索者可通过提交相同执行策略的复制或降级版本创建Sybil身份，验证者可能与搜索者合谋以增加联合收益。我们通过针对复制代码Sybil偏差及验证者-搜索者合谋偏差的贝叶斯安全约束解决这些问题。
英文摘要
Centralization in maximal extractable value (MEV) markets is a significant concern for blockchain systems, as persistent concentration of economic power can weaken competition, reduce openness, and undermine the decentralization goals of permissionless protocols. While much of the existing analysis has focused on builders, validators, and block-building markets, this paper studies centralization from the perspective of searcher competition. We develop a heterogeneous model in which searchers differ in opportunity coverage and execution efficiency, and we analyze how auction design affects fairness, decentralization, and security among searchers competing for the same MEV opportunity. To evaluate searcher competition, we introduce two metrics: a Shapley-weighted Jain fairness index, which measures whether rewards are proportional to searchers' marginal contributions, and an expected-reward Herfindahl-Hirschman Index (HHI), which measures concentration in long-run searcher rewards. Using these metrics, we first analyze the standard first-price, winner-take-all auction as a benchmark. Our analysis shows that, under searcher heterogeneity, first-price competition can reward rank dominance rather than marginal contribution, leading to concentrated rewards and weaker contribution-adjusted fairness. Motivated by these limitations, we propose an entry-filtered Shapley-capped auction mechanism that distributes searcher rewards more fairly and broadly among admitted high-quality submissions. Designing such a mechanism in a permissionless blockchain environment is challenging: searchers may create Sybil identities by submitting copied or degraded versions of the same execution strategy, and validators may collude with searchers to increase joint payoff. We address these concerns through Bayesian security constraints for copied-code Sybil deviations and validator-searcher coalition deviations.
