Projection in constraint logic programming (Diss., TU Berlin) (Q2726301)

The evaluation of programs leads typically to local variables which become inaccessible or dead. Many programming languages, including the logic programming language Prolog, contain a mechanism -- called garbarge collection -- which removes such variables. In the context of CLP (Contraint Logic Programming) dead variables can be considered as to be existentially quantified. Removing an existential quantifier can be understood as quantifier elimination or projection. Quantifier elimination has many benefits, in particular space recovering and decrease of cost for consistency checks. In the booklet this idea is exploited. The author introduces the notion of early projection and develops an architecture for automatic early projection in CLP (X). This architecture is applied to the two practical planning problems can-build and Fakos in realistic size. The author proposes solutions to these problems using CLP(RealNumbers) and CLP(FiniteDomains).