Corrigendum to “Min-domain retroactive ordering for asynchronous backtracking”

Abstract

The asynchronous backtracking algorithm with dynamic ordering (ABT_DO), proposed in Zivan and Meisels (Constraints 11(2–3):179–197, 2006), allows changing the order of agents during distributed asynchronous complete search. In a later study (Zivan et al., Constraints 14(2):177–198, 2009), retroactive heuristics which allowed more flexibility in the selection of new orders were introduced, resulting in the ABT_DO-Retro algorithm, and a relation between the success of heuristics and the min-domain property was identified. Unfortunately, the description of the time-stampping protocol used to compare orders in ABT_DO-Retro in Zivan et al. (Constraints 14(2):177–198, 2009) is confusing and may lead to an implementation in which ABT_DO-Retro may not terminate. In this corrigendum, we demonstrate the possible undesired outcome and give a detailed and formal description of the correct method for comparing time-stamps in ABT_DO-Retro.