n. PRO(gramming) LOG(ic): a high-level computer language that is important in artificial intelligence research. Inference in PROLOG is a form of deduction but is not mathematically sound due to several pragmatic compromises, including the use of “cut” to control backtracking and “negation” as the failure to find correct results. A strength of the language is a powerful pattern matcher based on unification, for use in production system applications.