CHAPTER 4 – Resolution

Publisher Summary This chapter discusses the clausal form of resolution. An inference procedure based on a simple yet extremely powerful rule of inference known as the resolution principle is presented. It uses just one rule of inference, and the procedure is simple to analyze, and implement, yet it is known to be both sound and, in a sense, complete. The resolution procedure takes as argument a set of expressions in a simplified version of predicate calculus, called clausal form. The symbols, terms, and atomic sentences of clausal form are the same as those in ordinary predicate calculus. Instead of logical and quantified sentences, however, clausal form has literals and clauses. A clause is a set of literals representing their disjunction. For any sentence in predicate calculus, there is a set of clauses that is equivalent to the original sentence in that the sentence is satisfiable only if the corresponding set of clauses is satisfiable.