Box consistency through weak box consistency

Interval constraint solvers use local consistencies-among which one worth mentioning is box consistency-for computing verified solutions of real constraint systems. Though among the most efficient ones, the algorithm for enforcing box consistency suffers from the use of time-consuming operators. This paper first introduces box_φ consistency, a weakening of box consistency; this new notion then allows us to devise an adaptive algorithm that computes box consistency by enforcing box_φ consistency, decreasing the φ parameter as variables´ domains get tightened, then achieving eventually box₀ consistency, which is equivalent to box consistency. A new propagation algorithm is also given, that intensifies the use of the most contracting pruning functions based on boxφ consistency. The resulting algorithm is finally shown to outperform the original scheme for enforcing box consistency on a set of standard benchmarks