TY  - JOUR
A1  - Brain, Martin
A1  - Gebser, Martin
A1  - Pührer, Jörg
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - "That is illogical, Captain!" : the debugging support tool spock for answer-set programs ; system description
Y1  - 2007
ER  - 
TY  - GEN
A1  - Gebser, Martin
A1  - Harrison, Amelia
A1  - Kaminski, Roland
A1  - Lifschitz, Vladimir
A1  - Schaub, Torsten H.
T1  - Abstract gringo
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - This paper defines the syntax and semantics of the input language of the ASP grounder gringo. The definition covers several constructs that were not discussed in earlier work on the semantics of that language, including intervals, pools, division of integers, aggregates with non-numeric values, and lparse-style aggregate expressions. The definition is abstract in the sense that it disregards some details related to representing programs by strings of ASCII characters. It serves as a specification for gringo from Version 4.5 on.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 592 
KW  - nested expressions
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-414751
SN  - 1866-8372
IS  - 592
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - Alternative characterizations for program equivalence under aswer-set semantics : a preliminary report
Y1  - 2007
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Sabuncu, Orkunt
A1  - Schaub, Torsten H.
T1  - An incremental answer set programming based system for finite model computation
JF  - AI communications : AICOM ; the European journal on artificial intelligence
N2  - We address the problem of Finite Model Computation (FMC) of first-order theories and show that FMC can efficiently and transparently be solved by taking advantage of a recent extension of Answer Set Programming (ASP), called incremental Answer Set Programming (iASP). The idea is to use the incremental parameter in iASP programs to account for the domain size of a model. The FMC problem is then successively addressed for increasing domain sizes until an answer set, representing a finite model of the original first-order theory, is found. We implemented a system based on the iASP solver iClingo and demonstrate its competitiveness by showing that it slightly outperforms the winner of the FNT division of CADE's 2009 Automated Theorem Proving (ATP) competition on the respective benchmark collection.
KW  - Incremental answer set programming
KW  - finite model computation
Y1  - 2011
U6  - https://doi.org/10.3233/AIC-2011-0496
SN  - 0921-7126
VL  - 24
IS  - 2
SP  - 195
EP  - 212
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Bomanson, Jori
A1  - Janhunen, Tomi
A1  - Schaub, Torsten H.
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
T1  - Answer Set Programming Modulo Acyclicity
JF  - Fundamenta informaticae
N2  - Acyclicity constraints are prevalent in knowledge representation and applications where acyclic data structures such as DAGs and trees play a role. Recently, such constraints have been considered in the satisfiability modulo theories (SMT) framework, and in this paper we carry out an analogous extension to the answer set programming (ASP) paradigm. The resulting formalism, ASP modulo acyclicity, offers a rich set of primitives to express constraints related to recursive structures. In the technical results of the paper, we relate the new generalization with standard ASP by showing (i) how acyclicity extensions translate into normal rules, (ii) how weight constraint programs can be instrumented by acyclicity extensions to capture stability in analogy to unfounded set checking, and (iii) how the gap between supported and stable models is effectively closed in the presence of such an extension. Moreover, we present an efficient implementation of acyclicity constraints by incorporating a respective propagator into the state-of-the-art ASP solver CLASP. The implementation provides a unique combination of traditional unfounded set checking with acyclicity propagation. In the experimental part, we evaluate the interplay of these orthogonal checks by equipping logic programs with supplementary acyclicity constraints. The performance results show that native support for acyclicity constraints is a worthwhile addition, furnishing a complementary modeling construct in ASP itself as well as effective means for translation-based ASP solving.
Y1  - 2016
U6  - https://doi.org/10.3233/FI-2016-1398
SN  - 0169-2968
SN  - 1875-8681
VL  - 147
SP  - 63
EP  - 91
PB  - IOS Press
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Anger, Christian
A1  - Gebser, Martin
A1  - Schaub, Torsten H.
T1  - Approaching the core of unfounded sets
Y1  - 2006
UR  - http://www.cs.uni-potsdam.de/wv/pdfformat/angesc06a.pdf
ER  - 
TY  - GEN
A1  - Schäpers, Björn
A1  - Niemueller, Tim
A1  - Lakemeyer, Gerhard
A1  - Gebser, Martin
A1  - Schaub, Torsten H.
T1  - ASP-Based Time-Bounded Planning for Logistics Robots
T2  - Twenty-Eighth International Conference on Automated Planning and Scheduling (ICAPS 2018)
N2  - Manufacturing industries are undergoing a major paradigm shift towards more autonomy. Automated planning and scheduling then becomes a necessity. The Planning and Execution Competition for Logistics Robots in Simulation held at ICAPS is based on this scenario and provides an interesting testbed. However, the posed problem is challenging as also demonstrated by the somewhat weak results in 2017. The domain requires temporal reasoning and dealing with uncertainty. We propose a novel planning system based on Answer Set Programming and the Clingo solver to tackle these problems and incentivize robot cooperation. Our results show a significant performance improvement, both, in terms of lowering computational requirements and better game metrics.
Y1  - 2018
SN  - 2334-0835
SN  - 2334-0843
SP  - 509
EP  - 517
PB  - ASSOC Association for the Advancement of Artificial Intelligence
CY  - Palo Alto
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Neumann, André
A1  - Schaub, Torsten H.
T1  - Clasp : a conflict-driven answer set solver
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaminski, Roland
A1  - Schaub, Torsten H.
T1  - Complex optimization in answer set programming
JF  - Theory and practice of logic programming
N2  - Preference handling and optimization are indispensable means for addressing nontrivial applications in Answer Set Programming (ASP). However, their implementation becomes difficult whenever they bring about a significant increase in computational complexity. As a consequence, existing ASP systems do not offer complex optimization capacities, supporting, for instance, inclusion-based minimization or Pareto efficiency. Rather, such complex criteria are typically addressed by resorting to dedicated modeling techniques, like saturation. Unlike the ease of common ASP modeling, however, these techniques are rather involved and hardly usable by ASP laymen. We address this problem by developing a general implementation technique by means of meta-prpogramming, thus reusing existing ASP systems to capture various forms of qualitative preferences among answer sets. In this way, complex preferences and optimization capacities become readily available for ASP applications.
KW  - Answer Set Programming
KW  - Preference Handling
KW  - Complex optimization
KW  - Meta-Programming
Y1  - 2011
U6  - https://doi.org/10.1017/S1471068411000329
SN  - 1471-0684
VL  - 11
IS  - 3
SP  - 821
EP  - 839
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - GEN
A1  - Gebser, Martin
A1  - Kaminski, Roland
A1  - Schaub, Torsten H.
T1  - Complex optimization in answer set programming
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - Preference handling and optimization are indispensable means for addressing nontrivial applications in Answer Set Programming (ASP). However, their implementation becomes difficult whenever they bring about a significant increase in computational complexity. As a consequence, existing ASP systems do not offer complex optimization capacities, supporting, for instance, inclusion-based minimization or Pareto efficiency. Rather, such complex criteria are typically addressed by resorting to dedicated modeling techniques, like saturation. Unlike the ease of common ASP modeling, however, these techniques are rather involved and hardly usable by ASP laymen. We address this problem by developing a general implementation technique by means of meta-prpogramming, thus reusing existing ASP systems to capture various forms of qualitative preferences among answer sets. In this way, complex preferences and optimization capacities become readily available for ASP applications.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 554 
KW  - answer set programming
KW  - preference handling
KW  - complex optimization
KW  - meta-programming
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412436
SN  - 1866-8372
IS  - 554
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Neumann, André
A1  - Schaub, Torsten H.
T1  - Conflict-driven answer set enumeration
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Neumann, André
A1  - Schaub, Torsten H.
T1  - Conflict-driven answer set solving
Y1  - 2007
SN  - 978-1-57735-323-2
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Kaufmann, Benjamin
A1  - Schaub, Torsten H.
T1  - Conflict-driven answer set solving: From theory to practice
JF  - Artificial intelligence
N2  - We introduce an approach to computing answer sets of logic programs, based on concepts successfully applied in Satisfiability (SAT) checking. The idea is to view inferences in Answer Set Programming (ASP) as unit propagation on nogoods. This provides us with a uniform constraint-based framework capturing diverse inferences encountered in ASP solving. Moreover, our approach allows us to apply advanced solving techniques from the area of SAT. As a result, we present the first full-fledged algorithmic framework for native conflict-driven ASP solving. Our approach is implemented in the ASP solver clasp that has demonstrated its competitiveness and versatility by winning first places at various solver contests.
KW  - Answer set programming
KW  - Logic programming
KW  - Nonmonotonic reasoning
Y1  - 2012
U6  - https://doi.org/10.1016/j.artint.2012.04.001
SN  - 0004-3702
VL  - 187
IS  - 8
SP  - 52
EP  - 89
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Brain, Martin
A1  - Gebser, Martin
A1  - Pührer, Jörg
A1  - Schaub, Torsten H.
A1  - Tompits, Hans
A1  - Woltran, Stefan
T1  - Debugging ASP programs by means of ASP
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Janhunen, Tomi
A1  - Rintanen, Jussi
T1  - Declarative encodings of acyclicity properties
JF  - Journal of logic and computation
N2  - Many knowledge representation tasks involve trees or similar structures as abstract datatypes. However, devising compact and efficient declarative representations of such structural properties is non-obvious and can be challenging indeed. In this article, we take a number of acyclicity properties into consideration and investigate various logic-based approaches to encode them. We use answer set programming as the primary representation language but also consider mappings to related formalisms, such as propositional logic, difference logic and linear programming. We study the compactness of encodings and the resulting computational performance on benchmarks involving acyclic or tree structures.
KW  - acyclicity properties
KW  - logic-based modeling
KW  - answer set programming
KW  - satisfiability
Y1  - 2015
U6  - https://doi.org/10.1093/logcom/exv063
SN  - 0955-792X
SN  - 1465-363X
VL  - 30
IS  - 4
SP  - 923
EP  - 952
PB  - Oxford Univ. Press
CY  - Eynsham, Oxford
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Schaub, Torsten H.
A1  - Thiele, Sven
A1  - Veber, Philippe
T1  - Detecting inconsistencies in large biological networks with answer set programming
JF  - Theory and practice of logic programming
N2  - We introduce an approach to detecting inconsistencies in large biological networks by using answer set programming. To this end, we build upon a recently proposed notion of consistency between biochemical/genetic reactions and high-throughput profiles of cell activity. We then present an approach based on answer set programming to check the consistency of large-scale data sets. Moreover, we extend this methodology to provide explanations for inconsistencies by determining minimal representations of conflicts. In practice, this can be used to identify unreliable data or to indicate missing reactions.
KW  - answer set programming
KW  - bioinformatics
KW  - consistency
KW  - diagnosis
Y1  - 2011
U6  - https://doi.org/10.1017/S1471068410000554
SN  - 1471-0684
VL  - 11
IS  - 5-6
SP  - 323
EP  - 360
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - GEN
A1  - Gebser, Martin
A1  - Schaub, Torsten H.
A1  - Thiele, Sven
A1  - Veber, Philippe
T1  - Detecting inconsistencies in large biological networks with answer set programming
T2  - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe
N2  - We introduce an approach to detecting inconsistencies in large biological networks by using answer set programming. To this end, we build upon a recently proposed notion of consistency between biochemical/genetic reactions and high-throughput profiles of cell activity. We then present an approach based on answer set programming to check the consistency of large-scale data sets. Moreover, we extend this methodology to provide explanations for inconsistencies by determining minimal representations of conflicts. In practice, this can be used to identify unreliable data or to indicate missing reactions.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 561 
KW  - answer set programming
KW  - bioinformatics
KW  - consistency
KW  - diagnosis
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412467
SN  - 1866-8372
IS  - 561
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Obermeier, Philipp
A1  - Otto, Thomas
A1  - Schaub, Torsten H.
A1  - Sabuncu, Orkunt
A1  - Van Nguyen, 
A1  - Tran Cao Son, 
T1  - Experimenting with robotic intra-logistics domains
JF  - Theory and practice of logic programming
N2  - We introduce the asprilo1 framework to facilitate experimental studies of approaches addressing complex dynamic applications. For this purpose, we have chosen the domain of robotic intra-logistics. This domain is not only highly relevant in the context of today's fourth industrial revolution but it moreover combines a multitude of challenging issues within a single uniform framework. This includes multi-agent planning, reasoning about action, change, resources, strategies, etc. In return, asprilo allows users to study alternative solutions as regards effectiveness and scalability. Although asprilo relies on Answer Set Programming and Python, it is readily usable by any system complying with its fact-oriented interface format. This makes it attractive for benchmarking and teaching well beyond logic programming. More precisely, asprilo consists of a versatile benchmark generator, solution checker and visualizer as well as a bunch of reference encodings featuring various ASP techniques. Importantly, the visualizer's animation capabilities are indispensable for complex scenarios like intra-logistics in order to inspect valid as well as invalid solution candidates. Also, it allows for graphically editing benchmark layouts that can be used as a basis for generating benchmark suites.
Y1  - 2018
U6  - https://doi.org/10.1017/S1471068418000200
SN  - 1471-0684
SN  - 1475-3081
VL  - 18
IS  - 3-4
SP  - 502
EP  - 519
PB  - Cambridge Univ. Press
CY  - New York
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Schaub, Torsten H.
T1  - Generic tableaux for answer set programming
Y1  - 2007
ER  - 
TY  - JOUR
A1  - Gebser, Martin
A1  - Schaub, Torsten H.
A1  - Thiele, Sven
T1  - GrinGo : a new grounder for answer set programming
Y1  - 2007
SN  - 978-3-540- 72199-4
ER  -