Nonmonotonic logical systems are logics in which the introduction of new axioms can invalidate old theorems. For practical applications, the authors restrict themselves to nonmonotonic systems that consist of facts and rules, and call them nonmonotonic knowledge-based systems (KBSs). Rules in a nonmonotonic KBS can be either default rules or regular rules. The syntax and semantics of these two types of rules are given. In contrast to other approaches, such as circumscription, default reasoning, assumption-based truth maintenance, and multi-valued logics, the authors directly extend the monotonic first order logic and its semantics. By using this method, one can define the validation problems for nonmonotonic KBSs similar to those for monotonic KBSs. Therefore, the validation tool already developed for monotonic KBSs can be extended to nonmonotonic KBSs.< >
article Free Access Share on Completeness of Linear Refutation for Theories with Equality Authors: C. L. Chang National Institutes of Health, Division of Computer Research and Technology, Public Health Service, Department of Health, Education and Welfare, Bethesda, Maryland National Institutes of Health, Division of Computer Research and Technology, Public Health Service, Department of Health, Education and Welfare, Bethesda, MarylandView Profile , J. R. Slagle National Institutes of Health, Division of Computer Research and Technology, Public Health Service, Department of Health, Education and Welfare, Bethesda, Maryland National Institutes of Health, Division of Computer Research and Technology, Public Health Service, Department of Health, Education and Welfare, Bethesda, MarylandView Profile Authors Info & Claims Journal of the ACMVolume 18Issue 1Jan. 1971 pp 126–136https://doi.org/10.1145/321623.321636Online:01 January 1971Publication History 13citation345DownloadsMetricsTotal Citations13Total Downloads345Last 12 Months9Last 6 weeks2 Get Citation AlertsNew Citation Alert added!This alert has been successfully added and will be sent to:You will be notified whenever a record that you have chosen has been cited.To manage your alert preferences, click on the button below.Manage my Alerts New Citation Alert!Please log in to your account Save to BinderSave to BinderCreate a New BinderNameCancelCreateExport CitationPublisher SiteeReaderPDF
A clustering and data-reorganizing algorithm based on the concept of the shortest spanning path of a graph is given. This algorithm can be used to reorganize and/or cluster a large file of data.
An improved program-synthesizing algorithm based on the algorithm proposed by Waldinger and Lee in 1969 is given. In the old algorithm, the program-synthesizing problem is translated into a theorem-proving problem, and a program is obtained by analyzing a proof. For the improved algorithm, the analysis is not necessary, and a program is obtained as soon as the proof is completed. This is achieved by using a modified variable tracing mechanism invented by Green in 1969. The correctness of the improved algorithm is also proved; i.e. the program thus obtained always satisfies the specification.
