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Justifications for programs with disjunctive and causal-choice rules*
Published online by Cambridge University Press: 14 October 2016
Abstract
In this paper, we study an extension of the stable model semantics for disjunctive logic programs where each true atom in a model is associated with an algebraic expression (in terms of rule labels) that represents its justifications. As in our previous work for non-disjunctive programs, these justifications are obtained in a purely semantic way, by algebraic operations (product, addition and application) on a lattice of causal values. Our new definition extends the concept of causal stable model to disjunctive logic programs and satisfies that each (standard) stable model corresponds to a disjoint class of causal stable models sharing the same truth assignments, but possibly varying the obtained explanations. We provide a pair of illustrative examples showing the behaviour of the new semantics and discuss the need of introducing a new type of rule, which we call causal-choice. This type of rule intuitively captures the idea of “A may cause B” and, when causal information is disregarded, amounts to a usual choice rule under the standard stable model semantics.
- Type
- Regular Papers
- Information
- Theory and Practice of Logic Programming , Volume 16 , Special Issue 5-6: 32nd International Conference on Logic Programming , September 2016 , pp. 587 - 603
- Copyright
- Copyright © Cambridge University Press 2016
Footnotes
This research was partially supported by Spanish Project TIN2013-42149-P.
References
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