Global cryptocurrencies are unbacked and have high transaction cost incurred by global consensus. In contrast, grassroots cryptocurrencies are backed by the goods and services of their issuers -- any person, natural or legal -- and have no transaction cost beyond operating a smartphone. Liquidity in grassroots cryptocurrencies arises from mutual credit via coin exchange among issuers. However, as grassroots coins are redeemable 1-for-1 against any other grassroots coin, the credit-forming exchange must also be 1-for-1, lest prompt redemption after exchange would leave the parties with undue profit or loss. Thus, grassroots coins are incongruent with liquidity through interest-bearing credit. Here we introduce grassroots bonds, which extend grassroots coins with a maturity date, reframing grassroots coins -- cash -- as mature grassroots bonds. Bond redemption generalises coin redemption, allowing the lending of liquid coins in exchange for interest-bearing future-maturity bonds. We show that digital social contracts -- voluntary agreements among persons, specified, fulfilled, and enforced digitally -- can express the full gamut of financial instruments as the voluntary swap of grassroots bonds, including loans, sale of debt, forward contracts, options, and escrow-based instruments, and that classical liquidity ratios are applicable just as well to grassroots bonds. Grassroots bonds may thus allow local digital economies to form and grow without initial capital or external credit, harnessing mutual trust within communities into liquidity. The formal specification presented here was implemented in GLP, a concurrent logic programming language running on Dart for smartphone deployment. The implementation is illustrated by a running multiagent village market scenario in GLP.

翻译：全球性加密货币无资产支撑，且因全球共识机制而产生高额交易成本。相比之下，草根加密货币以其发行人——任何自然人或法人——的商品和服务为支撑，除智能手机操作外无交易成本。草根加密货币的流动性源于发行人之间通过货币兑换实现的相互信贷。然而，由于草根币可按1:1比例兑换为任何其他草根币，信用形成的兑换也必须为1:1，否则兑换后立即赎回将导致各方产生不当盈亏。因此，草根币与通过有息信贷实现流动性的模式不相容。本文引入草根债券，通过为草根币附加到期日，将草根币（即现金）重构为到期的草根债券。债券赎回泛化了货币赎回机制，允许借出流动性货币以换取生息的远期到期债券。我们证明，数字社会契约——经数字化指定、履行和强制执行的个人间自愿协议——可通过草根债券的自愿交换表达全部金融工具，包括贷款、债务出售、远期合约、期权及托管型工具，且经典流动性比率同样适用于草根债券。草根债券因此可能使本地数字经济无需初始资本或外部信贷即可形成与发展，将社群内的互信转化为流动性。本文给出的形式化规范已通过GLP实现——这是一种运行于Dart平台、支持智能手机部署的并发逻辑编程语言。该实现通过GLP中运行的多智能体村庄市场场景进行演示。