Towards a theory of declarative knowledge
Foundations of deductive databases and logic programming
On the declarative semantics of deductive databases and logic programs
Foundations of deductive databases and logic programming
The alternating fixpoint of logic programs with negation
PODS '89 Proceedings of the eighth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Extended stable semantics for normal and disjunctive programs
Logic programming
Minimum and maximum predicates in logic programming
PODS '91 Proceedings of the tenth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Set constructors in a logic database language
Journal of Logic Programming
The well-founded semantics for general logic programs
Journal of the ACM (JACM)
The well-founded semantics of aggregation
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Modular stratification and magic sets for DATALOG programs with negation
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Three-valued formalization of logic programming: is it needed?
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Stable models and non-determinism in logic programs with negation
PODS '90 Proceedings of the ninth ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
New data models and languages—the challenge
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
The well-founded semantics of aggregation
PODS '92 Proceedings of the eleventh ACM SIGACT-SIGMOD-SIGART symposium on Principles of database systems
Database research at Wisconsin
ACM SIGMOD Record
On the power of algebras with recursion
SIGMOD '93 Proceedings of the 1993 ACM SIGMOD international conference on Management of data
Between Well-Founded Semantics and Stable Model Semantics
IDEAS '99 Proceedings of the 1999 International Symposium on Database Engineering & Applications
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We present the valid model semantics, a new approach to providing semantics for logic programs with negation, set-terms and grouping. The valid model semantics is a three-valued semantics, and is defined in terms of a ‘normal form’ computation. The valid model semantics also gives meaning to the generation and use of non-ground facts (i.e., facts with variables) in a computation.The formulation of the semantics in terms of a normal form computation offers important insight not only into the valid model semantics, but also into other semantics proposed earlier. We show that the valid model semantics extends the well-founded semantics in a natural manner, and has several advantages over it. The well-founded semantics can also be undertood using a variant of the normal form computations that we use; the normal form computations used for valid semantics seem more natural than those used for well-founded semantics.We also show that the valid model semantics has several other desirable properties: it is founded ([SZ90]), it is contained in every regular model ([YY90]), and it is contained in every two-valued stable model.