arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2001.00047cs.GT
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具有虚拟收益的联盟安全均衡

Coalition-Safe Equilibria with Virtual Payoffs

Aggelos Kiayias, Aikaterini-Panagiota Stouka

摘要:

考虑一组被邀请执行协议$Π$的各方。该协议将产生一些运行成本,而在最后(或定期),它将填充和更新分配(虚拟)奖励给参与者的本地表。每个参与者都希望通过协议过程中提供的虚拟收益来抵消参与成本。在这种情况下,我们引入并研究了联盟安全均衡的概念。特别是,我们考虑一个战略联盟的参与者,集中协调,并可能偏离$Π$的目的是增加其效用相对于其他参与者的{ \em至少一个}的看法。协议$Π$被称为联盟安全均衡与虚拟支付(EVP),如果没有这样的协议偏差存在。我们应用我们的概念来研究区块链协议中的激励机制。我们继续使用我们的框架来提供比特币区块链中激励的统一图景,对于基于绝对和相对奖励的效用函数,以及证明关于Fruitchain区块链协议激励的新结果[PODC 2017]证明了对于基于绝对报酬的效用函数,博弈双方合谋达到$n-1$的均衡条件成立,对于基于相对报酬的效用函数,博弈双方合谋小于$n/2$的均衡条件成立函数,后一个结果适用于任何“弱公平”区块链协议,这是我们引入的一个新属性,可能具有独立的兴趣。

英文摘要:

Consider a set of parties invited to execute a protocol $Π$. The protocol will incur some cost to run while in the end (or at regular intervals), it will populate and update local tables that assign (virtual) rewards to participants. Each participant aspires to offset the costs of participation by these virtual payoffs that are provided in the course of the protocol. In this setting, we introduce and study a notion of coalition-safe equilibrium. In particular, we consider a strategic coalition of participants that is centrally coordinated and potentially deviates from $Π$ with the objective to increase its utility with respect to the view of {\em at least one} of the other participants. The protocol $Π$ is called a coalition-safe equilibrium with virtual payoffs (EVP) if no such protocol deviation exists. We apply our notion to study incentives in blockchain protocols. We proceed to use our framework to provide a unified picture of incentives in the Bitcoin blockchain, for absolute and relative rewards based utility functions, as well as prove novel results regarding incentives of the Fruitchain blockchain protocol [PODC 2017] showing that the equilibrium condition holds for collusions up to $n-1$ players for absolute rewards based utility functions and less than $n/2$ for relative rewards based utility functions, with the latter result holding for any "weakly fair" blockchain protocol, a new property that we introduce and may be of independent interest.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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