Distributed Non-binary Constraints
Nowadays many real problems can be modeled as Constraint Satisfaction Problems (CSPs). In many situations, it is desirable to be able to state both hard constraints and soft constraints. Hard constraints must hold while soft constraints may be violated but as many as possible should be satisfied. Although the problem constraints can be divided into two groups, the order in which these constraints are studied can improve efficiency, particulary in problems with non-binary constraints. In this paper, we carry out a classification of hard and soft constraints in order to study the tightest hard constraints first and to obtain ever better solutions. In this way, inconsistencies can be found earlier and the number of constraint checks can be significantly reduced.