License: Creative Commons Attribution 3.0 Unported license (CC BY 3.0)
When quoting this document, please refer to the following
DOI: 10.4230/LIPIcs.OPODIS.2016.7
URN: urn:nbn:de:0030-drops-70761
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Delporte-Gallet, Carole ; Fauconnier, Hugues ; Gafni, Eli ; Kuznetsov, Petr

Set-Consensus Collections are Decidable

LIPIcs-OPODIS-2016-7.pdf (0.5 MB)


A natural way to measure the power of a distributed-computing model is to characterize the set of tasks that can be solved in it. In general, however, the question of whether a given task can be solved in a given model is undecidable, even if we only consider the wait-free shared-memory model. In this paper, we address this question for restricted classes of models and tasks. We show that the question of whether a collection C of (l, j)-set consensus objects, for various l (the number of processes that can invoke the object) and j (the number of distinct outputs the object returns), can be used by n processes to solve wait-free k-set consensus is decidable. Moreover, we provide a simple O(n^2) decision algorithm, based on a dynamic programming solution to the Knapsack optimization problem. We then present an adaptive wait-free set-consensus algorithm that, for each set of participating processes, achieves the best level of agreement that is possible to achieve using C. Overall, this gives us a complete characterization of a read-write model defined by a collection of set-consensus objects through its set-consensus power.

BibTeX - Entry

  author =	{Carole Delporte-Gallet and Hugues Fauconnier and Eli Gafni and Petr Kuznetsov},
  title =	{{Set-Consensus Collections are Decidable}},
  booktitle =	{20th International Conference on Principles of Distributed Systems (OPODIS 2016)},
  pages =	{7:1--7:15},
  series =	{Leibniz International Proceedings in Informatics (LIPIcs)},
  ISBN =	{978-3-95977-031-6},
  ISSN =	{1868-8969},
  year =	{2017},
  volume =	{70},
  editor =	{Panagiota Fatourou and Ernesto Jim{\'e}nez and Fernando Pedone},
  publisher =	{Schloss Dagstuhl--Leibniz-Zentrum fuer Informatik},
  address =	{Dagstuhl, Germany},
  URL =		{},
  URN =		{urn:nbn:de:0030-drops-70761},
  doi =		{10.4230/LIPIcs.OPODIS.2016.7},
  annote =	{Keywords: Decidability, distributed tasks, set consensus, Knapsack problem}

Keywords: Decidability, distributed tasks, set consensus, Knapsack problem
Collection: 20th International Conference on Principles of Distributed Systems (OPODIS 2016)
Issue Date: 2017
Date of publication: 06.04.2017

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