Guerraoui, RHerlihy, MPochon, B2006-10-052006-10-052006-10-05200610.1007/11945529_3https://infoscience.epfl.ch/handle/20.500.14299/234991This paper considers the k-set-agreement problem in a synchronous message passing distributed system where up to t processes can fail by crashing. We determine the number of communication rounds needed for all correct processes to reach a decision in a given run, as a function of k, the degree of coordination, and f <= t the number of processes that actually fail in the run. We prove a lower bound of min(\floor{f/k}+2,\floor{t/k}+1) rounds. Our proof uses simple topological tools to reason about runs of a full information set-agreement protocol. In particular, we introduce a new topological operator, which we call the early deciding operator, to capture rounds where k processes fail but correct processes see only k-1 failures.text::conference output::conference proceedings::conference paper