Gracefully Degrading Consensus and k-Set Agreement in Directed Dynamic Networks

  • Martin Biely
  • Peter Robinson
  • Ulrich Schmid
  • Manfred SchwarzEmail author
  • Kyrill Winkler
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9466)


We present (This work has been supported the Austrian Science Fund (FWF) project P26436 (SIC) and S11405 (RiSE).) the first consensus/k-set agreement algorithm for synchronous dynamic networks with unidirectional links, controlled by an omniscient message adversary, which automatically adapts to the actual network properties in a run: If the network is sufficiently well-connected, it solves consensus, while it degrades gracefully to general k-set agreement in less well-connected communication graphs. The actual number k of system-wide decision values is determined by the number of certain vertex-stable root components occurring in a run, which are strongly connected components without incoming links from outside. Related impossibility results reveal that our condition is reasonably close to the solvability border for k-set agreement.


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Copyright information

© Springer International Publishing Switzerland 2015

Authors and Affiliations

  • Martin Biely
    • 1
  • Peter Robinson
    • 2
  • Ulrich Schmid
    • 3
  • Manfred Schwarz
    • 3
    Email author
  • Kyrill Winkler
    • 3
  1. 1.EPFLLausanneSwitzerland
  2. 2.National University of SingaporeSingaporeSingapore
  3. 3.ECS GroupTU WienViennaAustria

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