Consensus with Max Registers

Authors James Aspnes, He Yang Er

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James Aspnes
  • Department of Computer Science, Yale University, New Haven, CT, USA
He Yang Er
  • Department of Computer Science, Yale University, New Haven, CT, USA

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James Aspnes and He Yang Er. Consensus with Max Registers. In 33rd International Symposium on Distributed Computing (DISC 2019). Leibniz International Proceedings in Informatics (LIPIcs), Volume 146, pp. 1:1-1:9, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2019)


We consider the problem of implementing randomized wait-free consensus from max registers under the assumption of an oblivious adversary. We show that max registers solve m-valued consensus for arbitrary m in expected O(log^* n) steps per process, beating the Omega(log m/log log m) lower bound for ordinary registers when m is large and the best previously known O(log log n) upper bound when m is small. A simple max-register implementation based on double-collect snapshots translates this result into an O(n log n) expected step implementation of m-valued consensus from n single-writer registers, improving on the best previously-known bound of O(n log^2 n) for single-writer registers.

Subject Classification

ACM Subject Classification
  • Theory of computation → Distributed algorithms
  • consensus
  • max register
  • single-writer register
  • oblivious adversary
  • shared memory


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