Generalized FLP impossibility result for t-resilient asynchronous computations
STOC '93 Proceedings of the twenty-fifth annual ACM symposium on Theory of computing
More choices allow more faults: set consensus problems in totally asynchronous systems
Information and Computation
Failure detectors and the wait-free hierarchy (extended abstract)
Proceedings of the fourteenth annual ACM symposium on Principles of distributed computing
Unreliable failure detectors for reliable distributed systems
Journal of the ACM (JACM)
The weakest failure detector for solving consensus
Journal of the ACM (JACM)
The topological structure of asynchronous computability
Journal of the ACM (JACM)
Wait-Free k-Set Agreement is Impossible: The Topology of Public Knowledge
SIAM Journal on Computing
A Realistic Look At Failure Detectors
DSN '02 Proceedings of the 2002 International Conference on Dependable Systems and Networks
The Weakest Failure Detector for Message Passing Set-Agreement
DISC '08 Proceedings of the 22nd international symposium on Distributed Computing
Weak Synchrony Models and Failure Detectors for Message Passing (k-)Set Agreement
OPODIS '09 Proceedings of the 13th International Conference on Principles of Distributed Systems
Tight failure detection bounds on atomic object implementations
Journal of the ACM (JACM)
Communication and Agreement Abstractions for Fault-tolerant Asynchronous Distributed Systems
Communication and Agreement Abstractions for Fault-tolerant Asynchronous Distributed Systems
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The k-set agreement problem is a coordination problem where each process is assumed to propose a value and each process that does not crash has to decide a value such that each decided value is a proposed value and at most k different values are decided. While it can always be solved in synchronous systems, k-set agreement has no solution in asynchronous send/receive messagepassing systems where up to t ≥ k processes may crash. A failure detector is a distributed oracle that provides processes with additional information related to failed processes and can consequently be used to enrich the computability power of asynchronous send/receive message-passing systems. Several failure detectors have been proposed to circumvent the impossibility of k-set agreement in pure asynchronous send/receive message-passing systems. Considering three of them (namely, the generalized quorum failure detector Σk, the generalized loneliness failure detector Lk and the generalized eventual leader failure detector Ωk) the paper investigates their computability power and the relations that link them. It has three mains contributions: (a) it shows that the failure detector Ωk and the eventual version of Lk have the same computational power; (b) it shows that Lk is realistic if and only if k ≥ n/2; and (c) it gives an exact characterization of the difference between Lk (that is too strong for k-set agreement) and Σk (that is too weak for k-set agreement).