Best--rst Search for Property M a I N - Tenance in Reactive Constraints Sys- Tems

Real-life dynamic problems may lead to inconsistent constraints systems for which a solution must be found even if constraints have to be relaxed. In this paper, we propose a bestrst search to handle such problems. Classical backtracking search algorithms are extended in two ways: identi cation of good backtrack points as in Intelligent Backtracking techniques and maximum use of independant work (that would have been discarded with a mere backtrack). We rst describe an operational semantics for our search method. Then we specialize it to handle constraint relaxation over nite domains. The practical use of this approach is demonstrated by theoretical complexity analysis and experiments.