On the mailbox problem

Uri Abraham, Gal Amram

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations


The Mailbox Problem was described and solved by Aguilera, Gafni, and Lamport in [2] with a mailbox algorithm that uses two flag registers that carry 14 values each. An interesting question that they ask is whether leaner solutions exists. In addition to their algorithm, the authors of [2] proved that the mailbox problem cannot be solved with 1 bit flags. In this paper, we show that 2 bit flags suffice by presenting a mailbox algorithm with two bit flags. The space complexity of Aguilera et al. solution is O(n log n) and they conjectured that a solution with space complexity O(log n) exists. Our algorithm proves this conjecture. We also prove that there is no mailbox algorithm with a smaller space complexity.

Original languageEnglish
Title of host publicationPrinciples of Distributed Systems - 18th International Conference, OPODIS 2014, Proceedings
EditorsMarcos K. Aguilera, Leonardo Querzoni, Marc Shapiro
PublisherSpringer Verlag
Number of pages16
ISBN (Electronic)9783319144719
StatePublished - 1 Jan 2014
Event18th International Conference on Principles of Distributed Systems, OPODIS 2014 - Cortina d’Ampezzo, Italy
Duration: 16 Dec 201419 Dec 2014

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference18th International Conference on Principles of Distributed Systems, OPODIS 2014
CityCortina d’Ampezzo


  • Distributed algorithms
  • Linearizability
  • Shared memory
  • Synchronization

ASJC Scopus subject areas

  • Theoretical Computer Science
  • Computer Science (all)


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