Foundations of Artificial Intelligence, Vol. 2, Suppl. (C), 2006
Chapter 6 Global Constraints
A global constraint is a constraint that captures a relation between a non-fixed number of variables. An example is the constraint alldifferent(x1, …, xn), which specifies that the values assigned to the variables x1, …, xn must be pairwise distinct. Typically, a global constraint is semantically redundant in the sense that the same relation can be expressed as the conjunction of several simpler constraints. Having shorthands for frequently recurring patterns clearly simplifies the programming task. What may be less obvious is that global constraints also facilitate ...