spock: A Debugging Support Tool for Logic Programs under the Answer-Set Semantics

2009 ◽  
pp. 247-252 ◽  
Author(s):  
Martin Gebser ◽  
Jörg Pührer ◽  
Torsten Schaub ◽  
Hans Tompits ◽  
Stefan Woltran
Keyword(s):  
Logic Programs ◽  
Support Tool ◽  
Answer Set Semantics ◽  
Answer Set

Tableau Calculi for Logic Programs under Answer Set Semantics

2013 ◽  
Vol 14 (2) ◽  
pp. 1-40 ◽  
Author(s):  
Martin Gebser ◽  
Torsten Schaub
Keyword(s):  
Logic Programs ◽  
Tableau Calculi ◽  
Answer Set Semantics ◽  
Answer Set

scholarly journals A program-level approach to revising logic programs under the answer set semantics

2010 ◽  
Vol 10 (4-6) ◽  
pp. 565-580 ◽  
Author(s):  
JAMES P. DELGRANDE
Keyword(s):  
Logic Program ◽  
Fundamental Principle ◽  
Logic Programs ◽  
Minimal Set ◽  
Essential Idea ◽  
The One ◽  
Answer Set Semantics ◽  
Answer Sets ◽  
Update Logic ◽  
Answer Set

AbstractAn approach to the revision of logic programs under the answer set semantics is presented. For programs P and Q, the goal is to determine the answer sets that correspond to the revision of P by Q, denoted P * Q. A fundamental principle of classical (AGM) revision, and the one that guides the approach here, is the success postulate. In AGM revision, this stipulates that α ∈ K * α. By analogy with the success postulate, for programs P and Q, this means that the answer sets of Q will in some sense be contained in those of P * Q. The essential idea is that for P * Q, a three-valued answer set for Q, consisting of positive and negative literals, is first determined. The positive literals constitute a regular answer set, while the negated literals make up a minimal set of naf literals required to produce the answer set from Q. These literals are propagated to the program P, along with those rules of Q that are not decided by these literals. The approach differs from work in update logic programs in two main respects. First, we ensure that the revising logic program has higher priority, and so we satisfy the success postulate; second, for the preference implicit in a revision P * Q, the program Q as a whole takes precedence over P, unlike update logic programs, since answer sets of Q are propagated to P. We show that a core group of the AGM postulates are satisfied, as are the postulates that have been proposed for update logic programs.

scholarly journals A general framework for equivalences in Answer-Set Programming by countermodels in the logic of Here-and-There

2011 ◽  
Vol 11 (2-3) ◽  
pp. 171-202 ◽  
Author(s):  
MICHAEL FINK
Keyword(s):  
General Framework ◽  
Answer Set Programming ◽  
Program Optimization ◽  
Logic Programs ◽  
Infinite Domains ◽  
General Semantics ◽  
Answer Set Semantics ◽  
Selection Of ◽  
Answer Set

AbstractDifferent notions of equivalence, such as the prominent notions of strong and uniform equivalence, have been studied in Answer-Set Programming, mainly for the purpose of identifying programs that can serve as substitutes without altering the semantics, for instance in program optimization. Such semantic comparisons are usually characterized by various selections of models in the logic of Here-and-There (HT). For uniform equivalence however, correct characterizations in terms of HT-models can only be obtained for finite theories, respectively programs. In this paper, we show that a selection of countermodels in HT captures uniform equivalence also for infinite theories. This result is turned into coherent characterizations of the different notions of equivalence by countermodels, as well as by a mixture of HT-models and countermodels (so-called equivalence interpretations). Moreover, we generalize the so-called notion of relativized hyperequivalence for programs to propositional theories, and apply the same methodology in order to obtain a semantic characterization which is amenable to infinite settings. This allows for a lifting of the results to first-order theories under a very general semantics given in terms of a quantified version of HT. We thus obtain a general framework for the study of various notions of equivalence for theories under answer-set semantics. Moreover, we prove an expedient property that allows for a simplified treatment of extended signatures, and provide further results for non-ground logic programs. In particular, uniform equivalence coincides under open and ordinary answer-set semantics, and for finite non-ground programs under these semantics, also the usual characterization of uniform equivalence in terms of maximal and total HT-models of the grounding is correct, even for infinite domains, when corresponding ground programs are infinite.

scholarly journals Possibilistic ASP Base Revision by Certain Input

2018 ◽  
Author(s):  
Laurent Garcia ◽  
Claire Lefèvre ◽  
Odile Papini ◽  
Igor Stéphan ◽  
Eric Würbel
Keyword(s):  
Answer Set Programming ◽  
Semantic Content ◽  
Logic Programs ◽  
Rule Based ◽  
Belief Base ◽  
Programming Framework ◽  
Base Revision ◽  
Possibilistic Logic ◽  
Answer Set Semantics ◽  
Answer Set

Belief base revision has been studied within the answer set programming framework. We go a step further by introducing uncertainty and studying belief base revision when beliefs are represented by possibilistic logic programs under possibilistic answer set semantics and revised by certain input. The paper proposes two approaches of rule-based revision operators and presents their semantic characterization in terms of possibilistic distribution. This semantic characterization allows for equivalently considering the evolution of syntactic logic programs and the evolution of their semantic content. It then studies the logical properties of the proposed operators and gives complexity results.

scholarly journals cc⊤: A Correspondence-Checking Tool for Logic Programs Under the Answer-Set Semantics

2006 ◽  
pp. 502-505 ◽  
Author(s):  
Johannes Oetsch ◽  
Martina Seidl ◽  
Hans Tompits ◽  
Stefan Woltran
Keyword(s):  
Logic Programs ◽  
Answer Set Semantics ◽  
Answer Set
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