A MULTI-VALUED LOGIC FOR PROGRAMMING

Date
1987-02-01
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
A logic using three truth values (true, false, undefined) is described together with its Horn clause subset and a procedural interpretation. The resulting logic programming language allows clauses to affirm both positive and negative information and can test whether a goal is definitely false or is just not provably true (standard negation by failure) as well as other possibilities including whether it is unknown (cannot be proven either true or false). The major theoretical results characterizing classical logic programs can be carried over to this context, including the equivalence of a programs answer set with the minimal Herbrand universe and least fixed point semantics as well as the correctness and completeness of SLD-resolution. The logic can be easily implemented within existing Prolog interpreters.
Description
Keywords
Computer Science
Citation