An automated market maker (AMM) is a state machine that manages pools of assets, allowing parties to buy and sell those assets according to a fixed mathematical formula. AMMs are typically implemented as smart contracts on blockchains, and its prices are kept in line with the overall market price by arbitrage: if the AMM undervalues an asset with respect to the market, an "arbitrageur" can make a risk-free profit by buying just enough of that asset to bring the AMM's price back in line with the market. AMMs, however, are not designed for assets that expire: that is, assets that cannot be produced or resold after a specified date. As assets approach expiration, arbitrage may not be able to reconcile supply and demand, and the liquidity providers that funded the AMM may have excessive exposure to risk due to rapid price variations. This paper formally describes the design of a decentralized exchange (DEX) for assets that expire, combining aspects of AMMs and limit-order books. We ensure liveness and market clearance, providing mechanisms for liquidity providers to control their exposure to risk and adjust prices dynamically in response to situations where arbitrage may fail.

翻译：自动做市商是一种状态机，负责管理资产池，允许各方根据固定的数学公式买卖这些资产。自动做市商通常以区块链上的智能合约形式实现，其价格通过套利机制与整体市场价格保持一致：如果自动做市商相对于市场低估了某项资产，"套利者"可以通过购买足够数量的该资产，使自动做市商的价格重新与市场保持一致，从而获取无风险利润。然而，自动做市商并非为到期资产（即在指定日期后无法生产或转售的资产）而设计。随着资产接近到期日，套利可能无法调节供需，且资助自动做市商的流动性提供者可能因价格快速波动而面临过度风险。本文正式描述了一种针对到期资产设计的去中心化交易所方案，该方案结合了自动做市商与限价订单簿的特点。我们确保系统的活跃性与市场出清，并为流动性提供者提供机制，使其能够控制风险敞口，并在套利可能失效的情况下动态调整价格。