Abstract
Existential rules are Datalog rules extended with existential quantifiers in rule-heads. Three fundamental restriction paradigms that have been studied for ensuring decidability of query answering under existential rules are weak-acyclicity, guardedness and stickiness. Towards the identification of even more expressive decidable languages, several attempts have been conducted to consolidate weak-acyclicity with the other two paradigms. However, it is not clear how guardedness and stickiness can be merged; this is the subject of this paper. A powerful and flexible condition, called tameness, is proposed, which allows us to consolidate in an elegant and uniform way guardedness with stickiness.
Original language | English |
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Pages (from-to) | 877-892 |
Number of pages | 16 |
Journal | TPLP |
Volume | 13 |
Issue number | 4-5 |
DOIs | |
Publication status | Published - Jul 2013 |