Optimization and relaxation in logic languages

摘要: This dissertation is concerned with the semantics, and applications of a logic programming language for specifying constraint optimization relaxation problems. The need arises naturally in various involving constraints, such as engineering design, document layout, interactive graphics, scheduling, decision support. In these settings one interested finding optimal solutions to constraints respect some objective function; and, if are impossible obtain, suboptimal either by relaxing function or themselves. While important practice, they meta-level operations--as require comparing alternative choosing best one--and therefore fall outside standard (CLP) framework. several approaches have been proposed literature address problems, do not provide unified, logical treatment both relaxation, nor flexibility our approach. Our thesis that concept preference provides natural, modular, declarative, efficient way expressing plays fundamental role sciences it gives rise notion extrema (minima maxima). We examine use two areas: databases grammars. Motivated potential deductive databases, we introduce database query called datalog. paradigm grammars (PLGs) means criteria disambiguating ambiguous