Abstract
In an important recent paper, Lin and Zhao introduced the concept of a loop formula, and showed that the answer sets for a logic program are exactly the models of Clark's completion of the program that satisfy the loop formulas. Just as supported sets are a model-theoretic account of completion, "externally supported" sets, defined in this paper, are a model-theoretic counterpart of loop formulas. This reformulation of loop formulas shows that they are related to assumption sets (Saccá and Zaniolo) and to unfounded sets (Van Gelder, Ross and Schlipf; Leone, Rullo and Scarcello), invented many years earlier. Other contributions of this paper includes a simplification of the definition of a loop, extending it to programs with classical negation and infinite programs, and a generalization of the definition of a loop formula.
Original language | English (US) |
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Title of host publication | IJCAI International Joint Conference on Artificial Intelligence |
Pages | 503-508 |
Number of pages | 6 |
State | Published - 2005 |
Externally published | Yes |
Event | 19th International Joint Conference on Artificial Intelligence, IJCAI 2005 - Edinburgh, United Kingdom Duration: Jul 30 2005 → Aug 5 2005 |
Other
Other | 19th International Joint Conference on Artificial Intelligence, IJCAI 2005 |
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Country/Territory | United Kingdom |
City | Edinburgh |
Period | 7/30/05 → 8/5/05 |
ASJC Scopus subject areas
- Artificial Intelligence