A Unifying Framework for ALP , CLP

This paper presents the TPCALP framework, a theorem-proving approach which aims to unify Abductive Logic Programming (ALP), Constraint Logic Programming (CLP) and Semantic Query Optimization (SQO). The framework combines the use of deenitions, as in ordinary logic programming, with the use of integrity constraints, as in ALP and SQO. The programmer can choose to represent knowledge in either form subject to the condition that the integrity constraints be \properties" of the deenitions. The paper deenes a proof procedure for the framework and presents some formal results for the proof procedure with respect to the framework semantics. The proof procedure executes deenitions in conventional logic programming goal reduction manner, and integrity constraints in forward reasoning style to check potential answers for consistency. The integrity constraints are used to process goals when the deenitions cannot be used, either because they are not accessible (as in ALP and SQO) or because their use would be computationally explosive (as in CLP and more generally).