The Generalized Loneliness Detector and Weak System Models for k-Set Agreement

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Original languageEnglish
Article number6482555
Pages (from-to)1078-1088
Journal / PublicationIEEE Transactions on Parallel and Distributed Systems
Issue number4
Online published19 Mar 2013
Publication statusPublished - Apr 2014
Externally publishedYes


This paper presents two weak partially synchronous system models Manti(n-k) and Msink(n-k) , which are just strong enough for solving k-set agreement: We introduce the generalized (n - k)-loneliness failure detector L(k), which we first prove to be sufficient for solving k-set agreement, and show that L(k) but not L(k - 1) can be implemented in both models. Manti(n-k) and Msink(n-k) are hence the first message passing models that lie between models where Ω (and therefore consensus) can be implemented and the purely asynchronous model. We also address k-set agreement in anonymous systems, that is, in systems where (unique) process identifiers are not available. Since our novel k-set agreement algorithm using L(k) also works in anonymous systems, it turns out that the loneliness failure detector L = L(n - 1) introduced by Delporte et al. is also the weakest failure detector for set agreement in anonymous systems. Finally, we analyze the relationship between L(k) and other failure detectors suitable for solving k-set agreement.

Research Area(s)

  • Distributed systems, models of computation