Perfect Derived Propagators.

When implementing a propagator for a constraint, one must decide about variants: When implementing min , should one also implement max ? Should one implement linear equations both with and without coefficients? Constraint variants are ubiquitous: implementing them requires considerable effort, but yields better performance. This paper shows how to use variable views to derive perfect propagator variants: derived propagators inherit essential properties such as correctness and domain and bounds completeness. [ABSTRACT FROM AUTHOR]