文章基本信息

标题：Expressive Power of Broadcast Consensus Protocols
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作者：Michael Blondin ; Javier Esparza ; Stefan Jaax 等
期刊名称：LIPIcs : Leibniz International Proceedings in Informatics
电子版ISSN：1868-8969
出版年度：2019
卷号：140
页码：1-16
DOI：10.4230/LIPIcs.CONCUR.2019.31
出版社：Schloss Dagstuhl -- Leibniz-Zentrum fuer Informatik
摘要：Population protocols are a formal model of computation by identical, anonymous mobile agents interacting in pairs. Their computational power is rather limited: Angluin et al. have shown that they can only compute the predicates over N^k expressible in Presburger arithmetic. For this reason, several extensions of the model have been proposed, including the addition of devices called cover-time services, absence detectors, and clocks. All these extensions increase the expressive power to the class of predicates over N^k lying in the complexity class NL when the input is given in unary. However, these devices are difficult to implement, since they require that an agent atomically receives messages from all other agents in a population of unknown size; moreover, the agent must know that they have all been received. Inspired by the work of the verification community on Emerson and Namjoshi's broadcast protocols, we show that NL-power is also achieved by extending population protocols with reliable broadcasts, a simpler, standard communication primitive.
关键词：population protocols; complexity theory; counter machines; distributed computing