DeltaStar: a general algorithm for incremental satisfaction of constraint hierarchies

The DeltaStar incremental algorithm for solving constraint hierarchies, which was developed as part of a continuing investigation on the design and implementation of constraint programming languages, is described. DeltaStar is a framework for incremental solvers built above an existing flat solver that provides the constraint solving techniques. By plugging different flat solvers into DeltaStar, different hierarchical solvers can quickly be produced and experimented with. Two implementations of DeltaStar, as well as previous algorithms that can be viewed as instances of DeltaStar, are discussed.<>