Results 1 - 10 of 671,700
- Journal of the ACM , 1991
"... . Set-grouping and aggregation are powerful non-monotonic operations of practical interest in database query languages. We consider the problem of expressing aggregation via negation as failure (NF). We study this problem in the framework of partial-order clauses introduced in [JOM95]. We show a tra ..."
Abstract - Cited by 4 (2 self) - Add to MetaCart
translation of partial-order programs to normal programs that is very natural: Any cost-monotonic partial-order program P becomes a stratified normal program transl(P) such that the declarative semantics of P is equivalent to the stratified semantics of transl(P). The ability to effect such a translation
- JOURNAL OF LOGIC PROGRAMMING , 1996
"... This paper presents for the first time the semantic foundations of CLP in a self-contained and complete package. The main contributions are threefold. First, we extend the original conference paper by presenting definitions and basic semantic constructs from first principles, giving new and comp ..."
Abstract - Cited by 872 (14 self) - Add to MetaCart
This paper presents for the first time the semantic foundations of CLP in a self-contained and complete package. The main contributions are threefold. First, we extend the original conference paper by presenting definitions and basic semantic constructs from first principles, giving new
- In Proceedings of International Symposium on Logic Programming , 1991
"... Classical fixpoint semantics for logic programs is based on the TP immediate consequence operator. The Kripke/Kleene, three-valued, semantics uses #P , which extends TP to Kleene's strong three-valued logic. Both these approaches generalize to cover logic programming systems based on a wide cla ..."
Abstract - Cited by 13 (2 self) - Add to MetaCart
class of logics, provided only that the underlying structure be that of a bilattice. This was presented in earlier papers. Recently well-founded semantics has become influential for classical logic programs. We show how the well-founded approach also extends naturally to the same family
"... We propose a new declarative semantics for logic programs with negation. Its formulation is quite simple; at the same time, it is more general than the iterated fixed point semantics for stratied programs, and is applicable to some useful programs that are not stratified. ..."
Abstract - Cited by 1833 (66 self) - Add to MetaCart
We propose a new declarative semantics for logic programs with negation. Its formulation is quite simple; at the same time, it is more general than the iterated fixed point semantics for stratied programs, and is applicable to some useful programs that are not stratified.
Smodels - an Implementation of the Stable Model and Well-Founded Semantics for Normal Logic Programs
"... The Smodels system is a C++ implementation of the wellfounded and stable model semantics for range-restricted function-free normal programs. The system includes two modules: (i) smodels which implements the two semantics for ground programs and (ii) parse which computes a grounded version of a range ..."
Abstract - Cited by 287 (9 self) - Add to MetaCart
-up backtracking search where a powerful pruning method is employed. The pruning method exploits an approximation technique for stable models which is closely related to the well-founded semantics. One of the advantages of this novel technique is that it can be implemented to work in linear space. This makes
"... We show that the well-founded semantics and the stable semantics are equivalent on the class of the order-consistent programs which is a strict super-class of the locally-stratified programs class and of the call-consistent programs class. (1) Université de Paris 1 90 rue de Tolbiac 75634 Paris ced ..."
Abstract - Cited by 1 (0 self) - Add to MetaCart
cedex 13 FRANCE email: email@example.com 2 1 Introduction This paper deals with the equivalence problem of two well-known semantics which have been proposed for general logic programs: the stable semantics () and the well-founded semantics ([15,2]). A general logic program is a set of rules
"... Bilattices, due to M. Ginsberg, are a family of truth value spaces that allow elegantly for missing or conflicting information. The simplest example is Belnap's four-valued logic, based on classical two-valued logic. Among other examples are those based on finite many-valued logics, and on prob ..."
Abstract - Cited by 444 (13 self) - Add to MetaCart
, and on probabilistic valued logic. A fixed point semantics is developed for logic programming, allowing any bilattice as the space of truth values. The mathematics is little more complex than in the classical two-valued setting, but the result provides a natural semantics for distributed logic programs, including
"... The realization of the Semantic Web vision, in which computational logic has a prominent role, has stimulated a lot of research on combining rules and ontologies, which are formulated in different formalisms, into a framework that is more useful for describing semantic content. In particular, combin ..."
Abstract - Cited by 74 (19 self) - Add to MetaCart
for the other main semantics of logic programs. It generalizes the canonical definition of the well-founded semantics based on unfounded sets, and, as we show, lifts many of the well-known properties from ordinary logic programs to dl-programs. Among these properties: our semantics amounts to a partial model
- Handbook of Philosophical Logic , 1984
"... ed to be true under the valuation u iff there exists an a 2 N such that the formula x = y is true under the valuation u[x=a], where u[x=a] agrees with u everywhere except x, on which it takes the value a. This definition involves a metalogical operation that produces u[x=a] from u for all possibl ..."
Abstract - Cited by 1008 (7 self) - Add to MetaCart
possible values a 2 N. This operation becomes explicit in DL in the form of the program x := ?, called a nondeterministic or wildcard assignment. This is a rather unconventional program, since it is not effective; however, it is quite useful as a descriptive tool. A more conventional way to obtain a