Combining constraints

Pattern name CombiningConstraints.
Context A basic constraint model.
Problem Insufficient propagation.
Forces Overhead of pruning combined constraint.
Additionally pruning provided by this combination.
Solution Introduce constraint that combines two or more of the basic constraints.
But only when they are likely to prune on a large number of common variables.
Example Combining sum and difference constraints in scheduling.
References A global constraint combining a sum constraint and difference constraints (citeseer)
Jean-Charles Regin and Michel Rueher Proceedings of CP-2000, 2000.