Search Results for author: Stefan Woltran

Found 28 papers, 3 papers with code

Rediscovering Argumentation Principles Utilizing Collective Attacks

no code implementations6 May 2022 Wolfgang Dvořák, Matthias König, Markus Ulbricht, Stefan Woltran

We extend the principle-based approach to Argumentation Frameworks with Collective Attacks (SETAFs) and provide a comprehensive overview of common principles for their semantics.

The Effect of Preferences in Abstract Argumentation Under a Claim-Centric View

no code implementations28 Apr 2022 Michael Bernreiter, Wolfgang Dvorak, Anna Rapberger, Stefan Woltran

In this paper, we study the effect of preferences in abstract argumentation under a claim-centric perspective.

Abstract Argumentation

Aspartix-V21

no code implementations7 Sep 2021 Wolfgang Dvořák, Matthias König, Johannes P. Wallner, Stefan Woltran

In this solver description we present ASPARTIX-V, in its 2021 edition, which participates in the International Competition on Computational Models of Argumentation (ICCMA) 2021.

Utilizing Treewidth for Quantitative Reasoning on Epistemic Logic Programs

1 code implementation6 Aug 2021 Viktor Besin, Markus Hecher, Stefan Woltran

In this paper, we take a next step and contribute to epistemic logic programming in two ways: First, we establish quantitative reasoning for ELPs, where the acceptance of a certain set of literals depends on the number (proportion) of world views that are compatible with the set.

Expressiveness of SETAFs and Support-Free ADFs under 3-valued Semantics

no code implementations7 Jul 2020 Wolfgang Dvořák, Atefeh Keshavarzi Zafarghandi, Stefan Woltran

Generalizing the attack structure in argumentation frameworks (AFs) has been studied in different ways.

Structural Decompositions of Epistemic Logic Programs

no code implementations13 Jan 2020 Markus Hecher, Michael Morak, Stefan Woltran

Epistemic logic programs (ELPs) are a popular generalization of standard Answer Set Programming (ASP) providing means for reasoning over answer sets within the language.

selp: A Single-Shot Epistemic Logic Program Solver

no code implementations4 Jan 2020 Manuel Bichler, Michael Morak, Stefan Woltran

Epistemic Logic Programs (ELPs) are an extension of Answer Set Programming (ASP) with epistemic operators that allow for a form of meta-reasoning, that is, reasoning over multiple possible worlds.

Translation

Solving Advanced Argumentation Problems with Answer Set Programming

no code implementations5 Dec 2019 Gerhard Brewka, Martin Diller, Georg Heissenberger, Thomas Linsbichler, Stefan Woltran

Powerful formalisms for abstract argumentation have been proposed, among them abstract dialectical frameworks (ADFs) that allow for a succinct and flexible specification of the relationship between arguments, and the GRAPPA framework which allows argumentation scenarios to be represented as arbitrary edge-labelled graphs.

Abstract Argumentation

On Uniform Equivalence of Epistemic Logic Programs

no code implementations25 Jul 2019 Wolfgang Faber, Michael Morak, Stefan Woltran

Epistemic Logic Programs (ELPs) extend Answer Set Programming (ASP) with epistemic negation and have received renewed interest in recent years.

Weighted Abstract Dialectical Frameworks: Extended and Revised Report

no code implementations20 Jun 2018 Gerhard Brewka, Jörg Pührer, Hannes Strass, Johannes P. Wallner, Stefan Woltran

Abstract Dialectical Frameworks (ADFs) generalize Dung's argumentation frameworks allowing various relationships among arguments to be expressed in a systematic way.

Exploiting Treewidth for Projected Model Counting and its Limits

no code implementations14 May 2018 Johannes K. Fichte, Michael Morak, Markus Hecher, Stefan Woltran

It runs in time $O({2^{2^{k+4}} n^2})$ where k is the treewidth and n is the input size of the instance.

When You Must Forget: beyond strong persistence when forgetting in answer set programming

no code implementations17 Jul 2017 Ricardo Gonçalves, Matthias Knorr, João Leite, Stefan Woltran

However, it is an open question what to do when we have to forget a set of atoms, but cannot without violating this property.

DynASP2.5: Dynamic Programming on Tree Decompositions in Action

1 code implementation28 Jun 2017 Johannes K. Fichte, Markus Hecher, Michael Morak, Stefan Woltran

In this paper, we describe underlying concepts of our new implementation (DynASP2. 5) that shows competitive behavior to state-of-the-art ASP solvers even for finding just one solution when solving problems as the Steiner tree problem that have been modeled in ASP on graphs with low treewidth.

Answer Set Solving with Bounded Treewidth Revisited

1 code implementation9 Feb 2017 Johannes Fichte, Markus Hecher, Michael Morak, Stefan Woltran

Parameterized algorithms are a way to solve hard problems more efficiently, given that a specific parameter of the input is small.

Counting Answer Sets via Dynamic Programming

no code implementations22 Dec 2016 Johannes Fichte, Markus Hecher, Michael Morak, Stefan Woltran

While the solution counting problem for propositional satisfiability (#SAT) has received renewed attention in recent years, this research trend has not affected other AI solving paradigms like answer set programming (ASP).

lpopt: A Rule Optimization Tool for Answer Set Programming

no code implementations19 Aug 2016 Manuel Bichler, Michael Morak, Stefan Woltran

State-of-the-art answer set programming (ASP) solvers rely on a program called a grounder to convert non-ground programs containing variables into variable-free, propositional programs.

The Power of Non-Ground Rules in Answer Set Programming

no code implementations5 Aug 2016 Manuel Bichler, Michael Morak, Stefan Woltran

In its traditional application, a fixed ASP program for a given problem is designed and the actual instance of the problem is fed into the program as a set of facts.

Clique-Width and Directed Width Measures for Answer-Set Programming

no code implementations30 Jun 2016 Bernhard Bliem, Sebastian Ordyniak, Stefan Woltran

We then consider the graph parameter of signed clique-width and present a novel dynamic programming algorithm that is FPT w. r. t.

Distributing Knowledge into Simple Bases

no code implementations31 Mar 2016 Adrian Haret, Jean-Guy Mailly, Stefan Woltran

In other words, we are interested in seeing if $K$ can be distributed into knowledge bases of simpler structure, such that the task of merging allows for a reconstruction of the original knowledge.

Verifiability of Argumentation Semantics

no code implementations31 Mar 2016 Ringo Baumann, Thomas Linsbichler, Stefan Woltran

Dung's abstract argumentation theory is a widely used formalism to model conflicting information and to draw conclusions in such situations.

Abstract Argumentation

Improved Answer-Set Programming Encodings for Abstract Argumentation

no code implementations23 Jul 2015 Sarah A. Gaggl, Norbert Manthey, Alessandro Ronca, Johannes P. Wallner, Stefan Woltran

The design of efficient solutions for abstract argumentation problems is a crucial step towards advanced argumentation systems.

Abstract Argumentation

Dual-normal Logic Programs - the Forgotten Class

no code implementations20 Jul 2015 Johannes K. Fichte, Miroslaw Truszczynski, Stefan Woltran

Identifying classes of programs for which the consistency problem is in NP is of interest from the theoretical standpoint and can potentially lead to improvements in the design of answer set programming solvers.

Translation

Compact Argumentation Frameworks

no code implementations30 Apr 2014 Ringo Baumann, Wolfgang Dvorák, Thomas Linsbichler, Hannes Strass, Stefan Woltran

(3) Finally, we show that compact AFs are indeed a non-trivial subclass, since the verification problem remains coNP-hard for certain semantics.

Abstract Argumentation Fairness

Belief merging within fragments of propositional logic

no code implementations25 Apr 2014 Nadia Creignou, Odile Papini, Stefan Rümmele, Stefan Woltran

This paper presents a general approach to define new merging operators derived from existing ones such that the result of merging remains in the fragment under consideration.

On the Intertranslatability of Argumentation Semantics

no code implementations16 Jan 2014 Wolfgang Dvorak, Stefan Woltran

Translations between different nonmonotonic formalisms always have been an important topic in the field, in particular to understand the knowledge-representation capabilities those formalisms offer.

Abstract Argumentation

Modularity Aspects of Disjunctive Stable Models

no code implementations15 Jan 2014 Tomi Janhunen, Emilia Oikarinen, Hans Tompits, Stefan Woltran

Practically all programming languages allow the programmer to split a program into several modules which brings along several advantages in software development.

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