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$\mathcal{ALE}$ Defeasible Description Logic [chapter]

Pakornpong Pothipruk, Guido Governatori
2006 Lecture Notes in Computer Science  
In this paper, we extend ALC − Defeasible Description Logic with existential quantifier, i.e., ALE Defeasible Description Logic.  ...  Also, we modify some parts of the logic, resulting in an increasing efficiency in its reasoning.  ...  He also proves that the complexity of ALC − defeasible description logic w.r.t. a defeasible description theory D is O(n 4 ), where n is the number of symbols in D.  ... 
doi:10.1007/11941439_15 fatcat:6u5upuwt6bfslmbe3iqowtw5vm

A Defeasible Logic for Clauses [chapter]

David Billington
2011 Lecture Notes in Computer Science  
CDL increases the expressive power of defeasible logic by allowing clauses where previous defeasible logics only allowed literals.  ...  CDL is the latest in the family of defeasible logics, which, it is argued, is important for knowledge representation and reasoning.  ...  To prove a literal l we must prove every clause in the set of antecedents of a strict or defeasible rule whose consequent is l.  ... 
doi:10.1007/978-3-642-25832-9_48 fatcat:f2hakmikoretvbihmdw44t2g3i

Approximating Defeasible Logics to Improve Scalability [article]

Michael J. Maher
2021 arXiv   pre-print
In this paper we consider the use of (implementations of) DL(∂_||) as a computational aid to computing conclusions in DL(∂) and other defeasible logics, rather than as an alternative to DL(∂).  ...  The defeasible logic DL(∂_||) was introduced as a more scalable alternative to DL(∂), which is better known.  ...  This is because the universal quantifier in (2.3) is vacuously satisfied.  ... 
arXiv:2108.05232v1 fatcat:hxndlirheragdjvm2scv7ubgke

An inclusion theorem for defeasible logics

David Billington, Grigoris Antoniou, Guido Governatori, Michael Maher
2010 ACM Transactions on Computational Logic  
This paper provides a compact presentation of the defeasible logic variants, and derives an Inclusion Theorem which shows that different notions of provability in defeasible logic form a chain of levels  ...  Defeasible reasoning is a computationally simple nonmonotonic reasoning approach that has attracted significant theoretical and practical attention.  ...  The only complication is that each universal quantifier in the proof rules is expressed with negations and (an implicit) existential quantifier.  ... 
doi:10.1145/1838552.1838558 fatcat:vozzguddfvahpaas7kpbirqkqi

Free Choice Permission in Defeasible Deontic Logic [chapter]

Guido Governatori, Antonino Rotolo
2020 Frontiers in Artificial Intelligence and Applications  
Accordingly, we investigate how to model the guarded form in Defeasible Deontic Logic extended with disjunctive permissions.  ...  In this paper, we follow a novel approach that accepts Free Choice Permission in a restricted form. The intuition behind the guarded form is strongly aligned with the idea of defeasibility.  ...  A rule is discarded if at least one of the literals in the antecedent has not been proved. Definition 5.  ... 
doi:10.3233/faia200853 fatcat:ou7whfjt7bca3mtxj7hqezwtka

Embedding defeasible logic into logic programming

2006 Theory and Practice of Logic Programming  
So far no relationship has been established between defeasible logic and mainstream nonmonotonic reasoning approaches. In this paper we establish close links to known semantics of logic programs.  ...  Defeasible logic and its variants are an important family of defeasible reasoning methods.  ...  Acknowledgements Preliminary versions of the material included in this paper appeared at AAAI'99 (Maher and Governatori 1999) and ICLP'02 (Antoniou and Maher 2002) .  ... 
doi:10.1017/s1471068406002778 fatcat:nht45fa4kzhg7lfavpmlgaysd4

On the relationship between Carneades and Defeasible Logic

Guido Governatori
2011 Proceedings of the 13th International Conference on Artificial Intelligence and Law - ICAIL '11  
The outcome of the investigation is that the current proof standards proposed in the Carneades framework correspond to some variants of Defeasible Logic.  ...  We study the formal relationships between the inferential aspects of Carneades (a general argumentation framework) and Defeasible Logic.  ...  Acknowledgements I would like to thank Thomas Gordon, Henry Prakken, Antonino Rotolo and Giovanni Sartor for discussions on the relationships between Carneades and Defeasible Logic.  ... 
doi:10.1145/2018358.2018362 dblp:conf/icail/Governatori11 fatcat:ic2lcvyv4ne2bldtmqczjriniu

Page 6595 of Mathematical Reviews Vol. , Issue 99j [page]

1999 Mathematical Reviews  
Janos Bagyinszki (Budapest) 99j:03023 03B60 03B70 68T27 Billington, David (5-GRIF-SI; Brisbane) Proving quantified literals in defeasible logic. (English summary) Inform.  ...  We describe a version of defeasible logic which is capable of proving existentially and uni- versally closed literals, as well as ground literals.  ... 

Strategic Argumentation is NP-Complete [article]

Guido Governatori, Francesco Olivieri, Simone Scannapieco, Antonino Rotolo, Matteo Cristani
2013 arXiv   pre-print
In this paper we study the complexity of strategic argumentation for dialogue games. A dialogue game is a 2-player game where the parties play arguments.  ...  We show how to model dialogue games in a skeptical, non-monotonic formalism, and we show that the problem of deciding what move (set of rules) to play at each turn is an NP-complete problem.  ...  In the remainder of this paper, we will study this research question in the context of Defeasible Logic.  ... 
arXiv:1312.4287v1 fatcat:nqkfmizmlzcinobf2clcarknvm

Rapid Text-Based Authoring of Defeasible Higher-Order Logic Formulas, via Textual Logic and Rulelog [chapter]

Benjamin N. Grosof
2013 Lecture Notes in Computer Science  
The resulting axioms are expressed as defeasible higher-order logic formulas in Rulelog, a novel extended form of declarative logic programs.  ...  Existential quantifiers are frequently required, and we describe Rulelog's approach to making existential knowledge be defeasible.  ...  TNF differs, in general, from Skolem normal form (used in FOL resolution theorem proving).  ... 
doi:10.1007/978-3-642-39617-5_2 fatcat:avpuxhcqebfb3jcprkjwynuffm

Page 3249 of Mathematical Reviews Vol. , Issue 96f [page]

1996 Mathematical Reviews  
Schwarz (Mountain View) 96f:03022 03B60 03B25 03B70 68T27 Nute, Donald (1-GA-AI; Athens, GA) A decidable quantified defeasible logic.  ...  a fragment of first-order logic); its defeasible part adds defeasible rules and defeater rules (the latter, like the former, connecting only literals) plus a unary operator of “tentative assertion”.  ... 

Defeasible preferences for intelligible pervasive applications to enhance eldercare

Johnson Fong, Ho-Pun Lam, Ricky Robinson, Jadwiga Indulska
2012 2012 IEEE International Conference on Pervasive Computing and Communications Workshops  
This paper presents a non-monotonic rule based approach (defeasible logic) for modelling user preferences, which serves as the basis of decision-making of application adaptations.  ...  It facilitates automatic generation of explanations regarding reasoning of defeasible preferences.  ...  They are specified using first order logic with a combination of facts supported by universal quantifiers and/or existential quantifiers as shown in figure 6 .  ... 
doi:10.1109/percomw.2012.6197580 dblp:conf/percom/FongLRI12 fatcat:xmjmj4zzgjctpbc23waltmab5u

A Modal Defeasible Reasoner of Deontic Logic for the Semantic Web

Efstratios Kontopoulos, Nick Bassiliades, Guido Governatori, Grigoris Antoniou
2011 International Journal on Semantic Web and Information Systems (IJSWIS)  
Defeasible and modal logics, in general, and, particularly, deontic logic can assist by providing means for modeling agent communities, where each agent is characterized by its own cognitive profile and  ...  Defeasible logic is a non-monotonic formalism that deals with incomplete and conflicting information, while modal logic deals with the concepts of necessity and possibility.  ...  definitely provable in D. • + ¶q, i.e. q is defeasibly provable in D. • - ¶q, i.e. we have proved that q is not defeasibly provable in D.  ... 
doi:10.4018/jswis.2011010102 fatcat:ec7a23vkqvfq5mlh4hiranmi2e

Temporalised normative positions in defeasible logic

Guido Governatori, Antonino Rotolo, Giovanni Sartor
2005 Proceedings of the 10th international conference on Artificial intelligence and law - ICAIL '05  
We argue about the defeasible nature of these notions and then we show how to represent and reason with them in the setting of Defeasible Logic.  ...  We propose a computationally oriented non-monotonic multi-modal logic arising from the combination of temporalised agency and temporalised normative positions.  ...  Knowledge in defeasible logic can be represented in two ways: facts and rules.  ... 
doi:10.1145/1165485.1165490 dblp:conf/icail/GovernatoriRS05 fatcat:afyhks3rmbhubkosu37dt5jxxu

Defeasibility, Law, and Argumentation: A Critical View from an Interpretative Standpoint

Francesca Poggi
2020 Argumentation: an international journal on reasoning  
In the legal field, the problems related to defeasibility have little in common with the problems that this label covers in other areas—such as logic or epistemology—and they are nothing but the well-known  ...  In conclusion, this paper argues that as far as legal argumentation is concerned, the notion of legal defeasibility lacks explanatory power, and it should be abandoned.  ...  I thank all the members of the audience for discussion, and in particular Alberto Artosi, Bruno Celano, Isabel Fanlo Cortés, Pablo Moreno Cruz, Giovanni Sartor, Corrado Roversi, Michele Ubertone, Vito  ... 
doi:10.1007/s10503-020-09544-w fatcat:nvfymbq3bje3roaj7u6y2npvri
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