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Full-Text Articles in Physical Sciences and Mathematics
Weighted-Sequence Problem: Asp Vs Casp And Declarative Vs Problem-Oriented Solving, Yuliya Lierler, Shaden Smith
Weighted-Sequence Problem: Asp Vs Casp And Declarative Vs Problem-Oriented Solving, Yuliya Lierler, Shaden Smith
Computer Science Faculty Proceedings & Presentations
Search problems with large variable domains pose a challenge to current answer-set programming (ASP) systems as large variable domains make grounding take a long time, and lead to large ground theories that may make solving infeasible. To circumvent the “grounding bottleneck” researchers proposed to integrate constraint solving techniques with ASP in an approach called constraint ASP (CASP). In the paper, we evaluate an ASP system clingo and a CASP system clingcon on a handcrafted problem involving large integer domains that is patterned after the database task of determining the optimal join order. We find that search methods used by clingo …
Parsing Combinatory Categorial Grammar With Answer Set Programming: Preliminary Report, Yuliya Lierler, Peter Schüller
Parsing Combinatory Categorial Grammar With Answer Set Programming: Preliminary Report, Yuliya Lierler, Peter Schüller
Computer Science Faculty Proceedings & Presentations
Combinatory categorial grammar (CCG) is a grammar formalism used for natural language parsing. CCG assigns structured lexical categories to words and uses a small set of combinatory rules to combine these categories to parse a sentence. In this work we propose and implement a new approach to CCG parsing that relies on a prominent knowledge representation formalism, answer set programming (ASP) — a declarative programming paradigm. We formulate the task of CCG parsing as a planning problem and use an ASP computational tool to compute solutions that correspond to valid parses. Compared to other approaches, there is no need to …
Sat-Based Answer Set Programming, Yuliya Lierler
Sat-Based Answer Set Programming, Yuliya Lierler
Computer Science Faculty Publications
Answer set programming (ASP) is a declarative programming paradigm oriented towards difficult combinatorial search problems. Syntactically, ASP programs look like Prolog programs, but solutions are represented in ASP by sets of atoms, and not by substitutions, as in Prolog. Answer set systems, such as SMODELS, SMODELSCC, and DLV, compute answer sets of a given program in the sense of the answer set (stable model) semantics. This is different from the functionality of Prolog systems, which determine when a given query is true relative to a given logic program. ASP has been applied to many areas of science and technology, from …
Experiments With Sat-Based Answer Set Programming, Enrico Giunchiglia, Yuliya Lierler, Marco Maratea, A. Tacchella
Experiments With Sat-Based Answer Set Programming, Enrico Giunchiglia, Yuliya Lierler, Marco Maratea, A. Tacchella
Computer Science Faculty Proceedings & Presentations
Answer Set Programming (ASP) emerged in the late 1990s as a new logic programming paradigm which has been successfully applied in various application domains. Propositional satisfiability (SAT) is one of the most studied problems in Computer Science. ASP and SAT are closely related: Recent works have studied their relation, and efficient SAT-based ASP solvers (like assat and Cmodels) exist. In this paper we report about (i) the extension of the basic procedures in Cmodels in order to incorporate the most popular SAT reasoning strategies, and (ii) an extensive comparative analysis involving also other state-of-the-art answer set solvers. The experimental analysis …
Disjunctive Answer Set Programming Via Satisfiability, Yuliya Lierler
Disjunctive Answer Set Programming Via Satisfiability, Yuliya Lierler
Computer Science Faculty Proceedings & Presentations
Using SAT solvers as inference engines in answer set programming systems showed to be a promising approach in building efficient systems. Nowadays SAT based answer set programming systems successfully work with nondisjunctive programs. This paper proposes a way to use SAT solvers for finding answer sets for disjunctive logic programs. We implement two different ways of SAT solver invocation used in nondisjunctive answer set programming. The algorithms are based on the definition of completion for disjunctive programs and the extension of loop formula to the disjunctive case. We propose the necessary modifications to the algorithms known for nondisjunctive programs in …
Sat-Based Answer Set Programming, Enrico Giunchiglia, Yuliya Lierler, Marco Maratea
Sat-Based Answer Set Programming, Enrico Giunchiglia, Yuliya Lierler, Marco Maratea
Computer Science Faculty Proceedings & Presentations
The relation between answer set programming (ASP) and propositional satisfiability (SAT) is at the center of many research papers, partly because of the tremendous performance boost of SAT solvers during last years. Various translations from ASP to SAT are known but the resulting SAT formula either includes many new variables or may have an unpractical size. There are also well known results showing a one-to-one correspondence between the answer sets of a logic program and the models of its completion. Unfortunately, these results only work for specific classes of problems. In this paper we present a SAT-based decision procedure for …