Name
Abstract | ||
|---|---|---|
A logic program consists of a set of Horn clauses, and can be used to express a query on relational data bases. It is shown that logic programs express precisely the queries in YE+ (the set of queries representable by a fixpoint applied to a positive existential query). Queries expressible by logic programs are thus not first-order queries in general, nor are all the first-order queries expressible as logic programs. Several ways of adding negation to logic programs are examined. The most general case is where arbitrary first-order formulas (with “nonterminal” relation symbols) are allowed. The resulting class has the expressive power of universally quantified second-order logic. |
Year | DOI | Venue |
|---|---|---|
1985 | 10.1016/0743-1066(85)90002-0 | The Journal of Logic Programming |
DocType | Volume | Issue |
Journal | 2 | 1 |
ISSN | Citations | PageRank |
0743-1066 | 182 | 107.78 |
References | Authors | |
58 | 2 | |
Name | Order | Citations | PageRank |
|---|---|---|---|
| Ashok K. Chandra | 1 | 3116 | 1215.02 |
| David Harel | 2 | 9703 | 1953.76 |