Maximal extractable value opportunities often induce spam in Layer-2 blockchains: many identical transactions are submitted near simultaneously, most of which revert, wasting blockspace. We study Timeboost, a mechanism on Arbitrum that auctions a timestamp advantage, crucial under first-come first-served sequencing rules. We develop a game-theoretic model in which users choose the number of transaction copies to submit, and extend upon the baseline setting by modeling the Timeboost auction and subsequent transaction submission behavior. We show that Timeboost reduces spam and increases sequencer/DAO revenue in equilibrium relative to the baseline, transferring user payments from revert costs to auction bids. Empirically, we assemble mempool data from multiple Layer-2 networks, measuring spam via identical transactions submitted in narrow time intervals, and conduct an event study around Timeboost adoption on Arbitrum using other L2s as contemporaneous benchmarks. We find a decline in MEV-related spam and an increase in revenue on Arbitrum post-adoption, consistent with model predictions.

翻译：最大可提取价值机会常引发Layer-2区块链中的垃圾交易现象：大量相同交易在相近时间被提交，其中多数最终回滚，造成区块空间浪费。本文研究Arbitrum网络采用的时间提升机制——该机制通过拍卖时间戳优先权，在"先到先得"的排序规则下具有关键作用。我们构建了一个博弈论模型，用户在该模型中选择提交交易副本的数量，并扩展基准场景以模拟时间提升拍卖及后续交易提交行为。研究表明，相较于基准机制，时间提升机制在均衡状态下能减少垃圾交易并提升定序器/DAO收入，将用户支付从回滚成本转移至拍卖竞价。实证方面，我们整合了多个Layer-2网络的内存池数据，通过窄时间窗口内提交的相同交易数量度量垃圾交易水平，并以其他L2网络作为同期对照，对Arbitrum采用时间提升机制进行了事件研究。实证发现Arbitrum在采用该机制后，MEV相关垃圾交易减少且收入增加，与模型预测一致。