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Papers by phan dung
Theoretical Computer Science, 1992
Dung, P.M., On the relations between stable and well-founded semantics of logic programs, Theoret... more Dung, P.M., On the relations between stable and well-founded semantics of logic programs, Theoretical Computer Science 105 (1992) 7-25.
Artificial Intelligence, 2006
We present a family of dialectic proof procedures for the admissibility semantics of assumption-b... more We present a family of dialectic proof procedures for the admissibility semantics of assumption-based argumentation. These proof procedures are defined for any conventional logic formulated as a collection of inference rules and show how any such logic can be extended to a dialectic argumentation system.
New Generation Computing, 1994
In this paper, we extend the partial deduction framework of Lloyd and Shepherdson, so that unfold... more In this paper, we extend the partial deduction framework of Lloyd and Shepherdson, so that unfolding of non-ground negative literals and loop checks can be carried out during partial deduction. We show that the unified framework is sound and complete wrt well-founded model semantics, when certain conditions are satisfied.
Two natural ways to specify the declarative semantics of logic programs and deductive databases a... more Two natural ways to specify the declarative semantics of logic programs and deductive databases are the fixpoint theory of Van Emden and Kowalski [11] and Clark's predicate completion [2]. The fixpoint theory does not apply to general programs with negation; a generalization of the theory can be defined [1,12] only if the programs are stratified. Clark's predicate completion is defined for logic programs with negation. In general, it fails to capture their intended semantics [7,8,9]. In this paper, we introduce a new notion of quasi-interpretation as a set of ground clauses of the form A ← ¬ B 1, ..., ← B n and extend the classic fixed point theory in [11] to quasi-interpretations. The semantics of a logic program P is defined by Clark's predicate completion of the least fixpoint of a continuous operator T P on quasi-interpretations. It is called the fixpoint completion of P, fixcomp(P). We then discuss the relations between fixcomp(P) and other approaches [5,7,8,9].
IEEE Transactions on Knowledge and Data Engineering, 2002
We study action rule based systems with two forms of negation, namely classical negation and &... more We study action rule based systems with two forms of negation, namely classical negation and "negation as failure to find a course of actions". We show by several examples that adding negation as failure to such systems increase their expressiveness, in the sense that real life problems can be represented in a natural and simple way. Then, we address the
We present a new argumentation-theoretic approach to default reasoning with speci-city. The new a... more We present a new argumentation-theoretic approach to default reasoning with speci-city. The new approach di ers from other approaches in the way priority between de-faults is handled. Here, it is context sensi-tive rather than context independent as in other ...
We study the conceptual relationship between the semantics of nonmonotonic inheritance reasoning ... more We study the conceptual relationship between the semantics of nonmonotonic inheritance reasoning and argumentation. We show that the credulous semantics of nonmonotonic inheritance network can be captured by the stable semantics of argumentation. We present a transformation of nonmonotonic inheritance networks into equivalent extended logic programs.
We apply logic program development technology to de ne abstract proof procedures, in the form of ... more We apply logic program development technology to de ne abstract proof procedures, in the form of logic programs, for computing the admissibility semantics for default reasoning proposed in 2]. The proof procedures are derived from a formal speci cation. The derivation guarantees the soundness of the proof procedures. The completeness of the proof procedures is shown by employing a technique of symbolic execution of logic programs to compute (an instance of) a relation implied by the speci cation.
We present a procedure for computing the sceptical "ideal semantics" for argumentation in assumpt... more We present a procedure for computing the sceptical "ideal semantics" for argumentation in assumption-based frameworks. This semantics was first proposed for logic programming in [1], extending the well-founded semantics. The proof procedure is defined by means of a form of dispute derivations, obtained by modifying the dispute derivations given in [2] for computing credulous admissible argumentation. The new dispute derivations are sound for the "ideal semantics" in all cases where the dispute derivations of [2] are complete for admissible argumentation. We prove that this is the case for the special kind of assumption-based frameworks with a finite underlying language and with the property of being "p-acyclic".
Abstract We present a coherent, flexible, unifying, and intuitive framework for the study of expl... more Abstract We present a coherent, flexible, unifying, and intuitive framework for the study of explicit negation in logic programs, based on the notion of admissible scenaria and the" coherence principle". With this support we introduce, in a simple way, a proposed" ideal sceptical semantics", as well as its wellfounded counterpart.
Page 1. The Acceptability Semantics for Logic Programs AC Kakas Dept. of Computer Science Univers... more Page 1. The Acceptability Semantics for Logic Programs AC Kakas Dept. of Computer Science University of Cyprus Kallipoleos 75 Nicosia, Cyprus antonis@jupiter.cca. ucy.cy P. Mancarella Dipartimento di Informatica Universit ...
We define abstract proof procedures for performing credulous and sceptical non-monotonic reasonin... more We define abstract proof procedures for performing credulous and sceptical non-monotonic reasoning, with respect to the argumentation-theoretic formulation of non-monotonic reasoning proposed in [1]. Appropriate instances of the proposed proof procedures provide concrete proof procedures for concrete formalisms for non-monotonic reasoning, for example logic programming with negation as failure and default logic. We propose (credulous and sceptical) proof procedures under different argumentation-theoretic semantics, namely the conventional stable model semantics and the more liberal partial stable model or preferred extension semantics. We study the relationships between proof procedures for different semantics, and argue that, in many meaningful cases, the (simpler) proof procedures for reasoning under the preferred extension semantics can be used as sound and complete procedures for reasoning under the stable model semantics. In many meaningful cases still, proof procedures for credulous reasoning under the preferred extension semantics can be used as (much simpler) sound and complete procedures for sceptical reasoning under the preferred extension semantics. We compare the proposed proof procedures with existing proof procedures in the literature.
Artificial Intelligence, 1997
We present an abstract framework for default reasoning, which includes Theorist, default logic, l... more We present an abstract framework for default reasoning, which includes Theorist, default logic, logic programming, autoepistemic logic, non-monotonic modal logics, and certain instances of circumscription as special cases. The framework can be understood as a generalisation of Theorist. The generalisation allows any theory formulated in a monotonic logic to be extended by a defeasible set of assumptions.
The Journal of Logic and Algebraic Programming, 1995
Theoretical Computer Science, 1992
Dung, P.M., On the relations between stable and well-founded semantics of logic programs, Theoret... more Dung, P.M., On the relations between stable and well-founded semantics of logic programs, Theoretical Computer Science 105 (1992) 7-25.
Artificial Intelligence, 2006
We present a family of dialectic proof procedures for the admissibility semantics of assumption-b... more We present a family of dialectic proof procedures for the admissibility semantics of assumption-based argumentation. These proof procedures are defined for any conventional logic formulated as a collection of inference rules and show how any such logic can be extended to a dialectic argumentation system.
New Generation Computing, 1994
In this paper, we extend the partial deduction framework of Lloyd and Shepherdson, so that unfold... more In this paper, we extend the partial deduction framework of Lloyd and Shepherdson, so that unfolding of non-ground negative literals and loop checks can be carried out during partial deduction. We show that the unified framework is sound and complete wrt well-founded model semantics, when certain conditions are satisfied.
Two natural ways to specify the declarative semantics of logic programs and deductive databases a... more Two natural ways to specify the declarative semantics of logic programs and deductive databases are the fixpoint theory of Van Emden and Kowalski [11] and Clark's predicate completion [2]. The fixpoint theory does not apply to general programs with negation; a generalization of the theory can be defined [1,12] only if the programs are stratified. Clark's predicate completion is defined for logic programs with negation. In general, it fails to capture their intended semantics [7,8,9]. In this paper, we introduce a new notion of quasi-interpretation as a set of ground clauses of the form A ← ¬ B 1, ..., ← B n and extend the classic fixed point theory in [11] to quasi-interpretations. The semantics of a logic program P is defined by Clark's predicate completion of the least fixpoint of a continuous operator T P on quasi-interpretations. It is called the fixpoint completion of P, fixcomp(P). We then discuss the relations between fixcomp(P) and other approaches [5,7,8,9].
IEEE Transactions on Knowledge and Data Engineering, 2002
We study action rule based systems with two forms of negation, namely classical negation and &... more We study action rule based systems with two forms of negation, namely classical negation and "negation as failure to find a course of actions". We show by several examples that adding negation as failure to such systems increase their expressiveness, in the sense that real life problems can be represented in a natural and simple way. Then, we address the
We present a new argumentation-theoretic approach to default reasoning with speci-city. The new a... more We present a new argumentation-theoretic approach to default reasoning with speci-city. The new approach di ers from other approaches in the way priority between de-faults is handled. Here, it is context sensi-tive rather than context independent as in other ...
We study the conceptual relationship between the semantics of nonmonotonic inheritance reasoning ... more We study the conceptual relationship between the semantics of nonmonotonic inheritance reasoning and argumentation. We show that the credulous semantics of nonmonotonic inheritance network can be captured by the stable semantics of argumentation. We present a transformation of nonmonotonic inheritance networks into equivalent extended logic programs.
We apply logic program development technology to de ne abstract proof procedures, in the form of ... more We apply logic program development technology to de ne abstract proof procedures, in the form of logic programs, for computing the admissibility semantics for default reasoning proposed in 2]. The proof procedures are derived from a formal speci cation. The derivation guarantees the soundness of the proof procedures. The completeness of the proof procedures is shown by employing a technique of symbolic execution of logic programs to compute (an instance of) a relation implied by the speci cation.
We present a procedure for computing the sceptical "ideal semantics" for argumentation in assumpt... more We present a procedure for computing the sceptical "ideal semantics" for argumentation in assumption-based frameworks. This semantics was first proposed for logic programming in [1], extending the well-founded semantics. The proof procedure is defined by means of a form of dispute derivations, obtained by modifying the dispute derivations given in [2] for computing credulous admissible argumentation. The new dispute derivations are sound for the "ideal semantics" in all cases where the dispute derivations of [2] are complete for admissible argumentation. We prove that this is the case for the special kind of assumption-based frameworks with a finite underlying language and with the property of being "p-acyclic".
Abstract We present a coherent, flexible, unifying, and intuitive framework for the study of expl... more Abstract We present a coherent, flexible, unifying, and intuitive framework for the study of explicit negation in logic programs, based on the notion of admissible scenaria and the" coherence principle". With this support we introduce, in a simple way, a proposed" ideal sceptical semantics", as well as its wellfounded counterpart.
Page 1. The Acceptability Semantics for Logic Programs AC Kakas Dept. of Computer Science Univers... more Page 1. The Acceptability Semantics for Logic Programs AC Kakas Dept. of Computer Science University of Cyprus Kallipoleos 75 Nicosia, Cyprus antonis@jupiter.cca. ucy.cy P. Mancarella Dipartimento di Informatica Universit ...
We define abstract proof procedures for performing credulous and sceptical non-monotonic reasonin... more We define abstract proof procedures for performing credulous and sceptical non-monotonic reasoning, with respect to the argumentation-theoretic formulation of non-monotonic reasoning proposed in [1]. Appropriate instances of the proposed proof procedures provide concrete proof procedures for concrete formalisms for non-monotonic reasoning, for example logic programming with negation as failure and default logic. We propose (credulous and sceptical) proof procedures under different argumentation-theoretic semantics, namely the conventional stable model semantics and the more liberal partial stable model or preferred extension semantics. We study the relationships between proof procedures for different semantics, and argue that, in many meaningful cases, the (simpler) proof procedures for reasoning under the preferred extension semantics can be used as sound and complete procedures for reasoning under the stable model semantics. In many meaningful cases still, proof procedures for credulous reasoning under the preferred extension semantics can be used as (much simpler) sound and complete procedures for sceptical reasoning under the preferred extension semantics. We compare the proposed proof procedures with existing proof procedures in the literature.
Artificial Intelligence, 1997
We present an abstract framework for default reasoning, which includes Theorist, default logic, l... more We present an abstract framework for default reasoning, which includes Theorist, default logic, logic programming, autoepistemic logic, non-monotonic modal logics, and certain instances of circumscription as special cases. The framework can be understood as a generalisation of Theorist. The generalisation allows any theory formulated in a monotonic logic to be extended by a defeasible set of assumptions.
The Journal of Logic and Algebraic Programming, 1995