M. Gelfond and V. Lifschitz. Representing Actions in Extended Logic Programming. In K. Apt, editor, Proc. of IJCSLP, 559--573. 1992.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....a sound and complete computation procedure for logic programs modelling actions and specificity. Finally, Section 7 discusses these results and outlines possible extensions. In particular, our results are related to a semantical approach to reason about actions developed by Gelfond and Lifschitz [11]. 2 Specificity In the introduction we have informally motivated specificity with the help of the Fragile Object example. In this section we will formally define specificity. To ease our presentation we restrict actions to those whose conditions and e#ect are ground. As we do not want to allow ....

....is broken after it was dropped, then we want to conclude that the object is fragile. Can we derive such a conclusion with our equational logic program To answer this question, we relate our approach to the action description language developed by Gelfond and Lifschitz. The language described in [11] consists of action names and fluent names, which might occur negated, along with expressions such as drop causes broken if fragile. 23) These so called e propositions describe the e#ect of an action (drop) on a single fluent (broken) provided a number of conditions (fragile) hold. The set of ....

M. Gelfond and V. Lifschitz. Representing Actions in Extended Logic Programming. In K. Apt, editor, Proc. of IJCSLP, 559--573. 1992.

....object to be broken. Specificity is incorporated into the equational logic approach using negation as failure and Clark s completion [10] In [37] it is shown that this extension can be used to correctly and completely implement the action description language A developed by Gelfond and Lifschitz [13]. As planning problems formulated in A can also be translated into into the situation calculus and into a circumscriptive scheme (see [22] this seems to be a good starting point in an attempt to tie the various approaches to deductive planning closer together. To summarize, the logics ....

M. Gelfond and V. Lifschitz. Representing actions in extended logic programming. In K. Apt, editor, Proceedings of the International Joint Conference and Symposium on Logic Programming, pages 559--573. MIT Press, 1992.

....1 INTRODUCTION The frame problem how to represent succinctly what remains unchanged as a result of performing an action has long been a challenge for many researchers in Artificial Intelligence. Several solutions have been proposed (see e.g. Pednault, 1989; Baker, 1991; Reiter, 1991; Gelfond and Lifschitz, 1992; Kartha and Lifschitz, 1995 ] some of these proposals have been formally compared [ Kartha, 1993 ] and there is the feeling that at least for domains without ramification constraints the frame problem is solved. In this paper we address the frame problem in presence of ramification ....

.... the second order formulas to first order equivalent ones (Section 4) Finally (Section 5) we show that the class of intended models of a domain in the situation calculus entails exactly the same conclusions entailed by the corresponding domain description in a high level action language like A [ Gelfond and Lifschitz, 1992 ] AR 0 [ Kartha and Lifschitz, 1994 ] or AR [ Giunchiglia et al. 1996 ] The novelties and motivations of each of the above four steps are the following. Definitions similar to our definition of minimally abnormal model have already been proposed in the literature [ Lin and Shoham, 1991; ....

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Michael Gelfond and Vladimir Lifschitz. Representing actions in extended logic programming. In Krzysztof Apt, editor, Proc. Joint Int'l Conf. and Symp. on Logic Programming, pages 559--573, 1992.

....as the Language A and the Situation Calculus. Posted and under public review in the News Journal of Electronic Transactions on Artificial Intelligence (ETAI) http: www.ida.liu.se ext etai 1 1 Introduction The idea of action description languages was first introduced by Gelfond and Lifschitz [7, 8], with their proposal for the Language A. The intention was that such languages would have a specialised syntax and semantics, and would be at a high enough level of abstraction so as to be easily readable, understandable and intuitive. They could then be used as specifications for theories of ....

.... :F holds at T is represented by the literal HoldsAt(Neg(F ) T ) F holds at T is represented by the literal HoldsAt(Pos(F ) T ) The negative literal not HoldsAt(F; T ) is simply interpreted as the t proposition F holds at T is not provable . Similar techniques are also used in [20] [7], 6] and [2] It is convenient to define translation operators and which convert E fluent literals to program terms such as Pos(F ) and Neg(F ) Definition 19 [lp term and lp complement] Given a fluent literal L of E = h Pi; Delta; Phii, the lp term of L, written (L) is defined to be ....

Michael Gelfond and Vladimir Lifschitz, Representing Actions in Extended Logic Programming, Proceedings of the Joint International Conference and Symposium on Logic Programming, ed. Krzysztof Apt, MIT Press, page 560, 1992.

....these can lead to car loss) the car couldn t have been lost during the day. The even weaker assumption that there were no Leave car overnight actions on the given days would have been sucient, as well. obs1 [0]p chr1 [t 1 ; t 2 ]do(I ;Leave car overnight) t 1 ; t 2 ) 2 f(0; 2) 4; 6)g obs2 [8]:p e 1 [t 1 ] p ) t 1 ; t 2 ] p exp1 [t 1 ; t 2 ]p : F ) t 1 : t 2 ]do(I ;Leave car overnight) Random, but probable events: Ticketed Car Problem (TCP) In some nonmonotonic approaches to the SCP above, the theft of the car would be treated as an exceptional event, and this will a ect the ....

....of times t at which [t] p holds. stat1 [ t] p] t :99 obs1 [0] r chr1 [t 1 ; t 2 ]do(Joe; y) t 1 ; t 2 ; y) 6; 8; Start) e 1 [t 1 ] p [t 1 ; t 2 ]do(Joe; Start) t 2 ]r Reasoning: We appeal directly to the model theoretic de nition of epistemic probabilities [6] Essentially P rob([8]rjKB) where KB = stat1 obs1 chr1 eff1, is the proportion of models of KB in which [8]r holds. More exactly, one considers the limit ratio as the number of time points comprising the time domain approaches 1. Let the number of interpretations of p satisfying stat1 be M (for some xed nite ....

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M. Gelfond and V. Lifschitz. Representing actions in extended logic programming. In K. Apt, editor, Proc. of the Joint Int. Conf. and Symp. on Logic Programming, pages 558-573. MIT Press, 1992.

....propagated via such statements, whilst retaining E s simple approach to the frame problem. This results in a simple model of causality appropriate for many domains involving actions and change. Introduction The idea of action description languages was first introduced by Gelfond and Lifschitz [6, 7], with their proposal for the Language A. The intention was that such languages would have a specialised syntax and semantics, and would be at a high enough level of abstraction so as to be easily readable, understandable and intuitive. They could then be used as specifications for theories of ....

Michael Gelfond and Vladimir Lifschitz, Representing Actions in Extended Logic Programming, Proceedings of the Joint International Conference and Symposium on Logic Programming, ed. Krzysztof Apt, MIT Press, page 560, 1992.

....is caused to hold and what actually holds in a model (though the word caused is not always employed) Next we compare S 0 to two ADL approaches: Baral and Gelfond s L 3 [3] and McCain and Turner s [21] Theory of Ramifications and Qualifications. L 3 is an extension of the well known language A [8] that can deal with concurrent actions, incomplete specification of actions and incomplete knowledge on the order of the observations in time; it cannot at all deal with ramifications. McCain and Turner (MT) s approach however is specifically geared to handle these, but cannot handle the other ....

M. Gelfond and V. Lifschitz. Representing actions in extended logic programming. In K. Apt, editor, Logic Programming: Proceedings Tenth Conference, pages 559--573, 1992.

....theories to model default reasoning. As regards the non narrative aspects of reasoning about action, various results enable a network of correspondences between formalisms to be built up. For example, Kartha [6] shows a correspondence between Baker s formalism and the Language A introduced in [5]. Furthermore, Gelfond and Lifschitz [5] Dung [4] Baral and Gelfond [2] and Denecker and De Schreye [3] have each shown how the Language A can be used as a specification for various logic programming formulations. Like the work in this paper, most results are restricted to cases where theories ....

....As regards the non narrative aspects of reasoning about action, various results enable a network of correspondences between formalisms to be built up. For example, Kartha [6] shows a correspondence between Baker s formalism and the Language A introduced in [5] Furthermore, Gelfond and Lifschitz [5], Dung [4] Baral and Gelfond [2] and Denecker and De Schreye [3] have each shown how the Language A can be used as a specification for various logic programming formulations. Like the work in this paper, most results are restricted to cases where theories are fluent independent . ....

Michael Gelfond and Vladimir Lifschitz, Representing Actions in Extended Logic Programming, Proceedings of the Joint International Conference and Symposium on Logic Programming, ed. Krzysztof Apt, MIT Press, page 560, 1992.

....ECSTER colloquium debate on Approaches to Reasoning About Actions and Change http: vir.liu.se brs news 96deb 03 23.12.1996 Comparing Action Formalisms: A Preliminary Position Statement Rob Miller Imperial College, London, England Here are some fairly miscellaneous thoughts about comparing ....

....ECSTER colloquium debate on Approaches to Reasoning About Actions and Change http: vir.liu.se brs news 96deb 03 23. 12.1996 Comparing Action Formalisms: A Preliminary Position Statement Rob Miller Imperial College, London, England Here are some fairly miscellaneous thoughts about comparing alternative approaches to Reasoning about Action. Please forgive me for a few fairly blatant attempts to advertise my ....

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Michael Gelfond and Vladimir Lifschitz, Representing Actions in Extended Logic Programming, Proceedings of the Joint International Conference and Symposium on Logic Programming, ed. Krzysztof Apt, MIT Press, page 560, 1992.

....is monotonic 1st order theories as the target for implementation. 6 Consequently, one can appeal to classical theorem provers or logic programming as a vehicle for implementation. There are a number of related results in this area which could prove useful. Some representative references are: [22], 25] 27] 29] 34] Additionally, the technique of explanation closure has very strong connections with syntactic based approaches ( 36] 38] In fact, it is becoming increasingly more popular and can be explained in terms of circumscriptive reductions which provide a means for ....

M. Gelfond and V. Lifschitz. Representing actions in extended logic programming. In K. Apt, editor, Proc. Joint Int'l Conf. and Symp. on Logic Programming, pages 559--573, 1992.

....before it has exploded, it would be necessary to model the mechanism by which the delayed effect otherwise comes to pass. This can be done by using the general approach illustrated in the next section. 11 11 Mendez, Lobo, Llopis, and Baral [1996] have defined an extension of the language A of Gelfond and Lifschitz [1992] which allows one to refer to facts about past states of the world in the preconditions of effect propositions. Since there are no restrictions on the time references that may appear in the antecedents and consequents of causal laws, references of a similar kind are possible in the language of ....

Michael Gelfond and Vladimir Lifschitz. Representing actions in extended logic programming. In Krzysztof Apt, editor, Proc. Joint Int'l Conf. and Symp. on Logic Programming, pages 559--573, 1992.

....The comparisons are made by means of set inclusion with respect to the range of applicability of the compared methods. 67 7.5.1 FC and the A Language compared In a recent work, M. Thielscher [Thi94] provided an assessing analysis of the Action Description Language A of Gelfond and Lifschitz [GL92, GL93] for which the range of applicability of the A language results to be the K IbsAd class of reasoning problems. The Fluent Calculus, which actual range of applicability is K RACi , has a broader range of applicability than the A language, since K IbsAd is a subclass of K RACi . 7.5.2 FC ....

M. Gelfond and V. Lifschitz. Representing actions in extended logic programming. In K. Apt, editor, Proceedings of the 9th International Joint Conference and Symposium on Logic Programming, pages 559-- 573, 1992.

....to information about e ects of later actions over e ects of earlier actions; 2) to develop an argumentation based computational model for this type of reasoning in logic programming goal driven style. 1 Introduction The idea of specialised action description languages was rst introduced in [7, 8] (and here exempli ed by the Language A) with the aim that such languages could serve as speci cations for theories of action and change written in di erent, general purpose or computation oriented formalisms. One such language is the Language E [10] designed to describe domains involving ....

.... is the Language E [10] designed to describe domains involving narrative information, i.e. information about actual occurrences of actions, using a basic ontology of actions, uents and time points inspired by the Event Calculus [12, 13] This paper contributes to the research agenda suggested in [7, 8] by showing how a signi cant class of E domains may be translated into the argumentation framework of Logic Programming without Negation as Failure (LPwNF) 4] and thus be given an argumentation based, goal driven proof theory. LPwNF uses a priority relation between potentially con icting or ....

M. Gelfond and V. Lifschitz. Representing Actions in Extended Logic Programming. JICSLP'92, 560, MIT Press.

....as the Language A and the Situation Calculus. Posted and under public review in the News Journal of Electronic Transactions on Artificial Intelligence (ETAI) http: www.ida.liu.se ext etai 1 1 Introduction The idea of action description languages was first introduced by Gelfond and Lifschitz [5, 6], with their proposal for the Language A. The intention was that such languages would have a specialised syntax and semantics, and would be at a high enough level of abstraction so as to be easily readable, understandable and intuitive. They could then be used as specifications for theories of ....

.... :F holds at T is represented by the literal HoldsAt(Neg(F ) T ) F holdsat T is represented by the literal HoldsAt(Pos(F ) T ) The negative literal not HoldsAt(F; T ) is simply interpreted as the t proposition F holds at T is not provable . Similar techniques are also used in [18] [5], 4] and [2] It is convenient to define translation operators and which convert E fluent literals to program terms such as Pos(F ) and Neg(F ) Definition 19 [lp term and lp complement] Given a fluent literal L of E = h Pi; Delta; Phii, the lp term of L, written (L) is defined to be ....

Michael Gelfond and Vladimir Lifschitz, Representing Actions in Extended Logic Programming, Proceedings of the Joint International Conference and Symposium on Logic Programming, ed. Krzysztof Apt, MIT Press, page 560, 1992.

.... 43] More recently, other extensions have been proposed to further enrich the expressive power of LP in order to turn it into a general formalism for knowledge representation (for a survey, see [15] Among others, we mention abductive LP [42, 35, 48] and LP with different forms of negation (e.g. [45, 56, 46, 52, 60, 10]) In particular, in [60] it is shown how logic programs with two kinds of negation (i.e. default and explicit negation) is applied to diverse domains of knowledge representation such as hierarchies and reasoning about actions. The formalization of these extensions has called for new semantics ....

....programming by introducing other forms of negation beyond negation by default. Different kinds of negation have been studied in the literature such as pseudo, classical, strong, weak and explicit negation and their usage for knowledge representation purposes has been investigated (e.g. see [10, 46, 52, 60]) A general framework dealing with many of these forms of negation is described in [6] In this section, we first show how one of these forms of negation, called pseudo negation, can be modeled in the framework introduced in the previous section for normal logic programs. We then discuss how ....

M. Gelfond, and V. Lifschitz. Representing Actions in Extended Logic Programming. In K. Apt, editor, Proc. Int. Joint Conf. and Symp. on Logic Programming, pages 559573. The MIT Press, 1992.

.... of Hilog and Tabling 71 Negation Similar meta interpreters transformations can be performed for ffl Head Cycle Free Disjunctive Logic Programs [10] ffl Generalized Horn Programs [12] ffl Extended Databases [117, 109] ffl Imex Negation [56] ffl A restriction to WFS of the action language A [47]. Tabling can also be used as a preprocessor for stable model computations. 72 Negation An Extended Logic Program (C. Damasio) perforation(X) suddenpain(X) abdtenderness(X) peritonealirritation(X) notbelieved highamylase(X) pancreatitis(X) suddenpain(X) abdtenderness(X) ....

M. Gelfond and V. Lifshitz. Representing actions in extended logic programming. In Joint Int'l Conf and Symp on Logic Programming, pages 559--573, 1992. 89

.... to model and investigate the Closed World Assumption [Rei78] inheritance networks with exceptions [ER83] and situations with conflicting default assumptions [RC81] Formalizations of the frame problem and reasoning about action in default logic were extensively studied in [Rei80, HM86, Gin86, GL92] Applications of default logic to diagnosis are discussed in [Rei87, Poo89] Default logic provides also a semantics for normal logic programs with negation. In [MT89] we described an encoding of logic programs as default theories, under which there is a straightforward one to one correspondence ....

M. Gelfond and V. Lifschitz. Representing actions in extended logic programming. In Proceedings of International Joint Conference and Symposium on Logic Programming, pages 559--573. MIT Press, 1992.

....of an action occurrence. Examples of such formalisms are Allen s interval based approach[1]andKowalski and Sergot s Event Calculus [20] On the other hand, formalismssuchasthe McCarthy and Hayes Situation Calculus [23] Dynamic Logics (see for example [14] and Gelfond and Lifschitz s Language A [13] are not narrative based. This is not to say that they cannot be extended to deal with narrative information (see for example [27] 25] or [21] But the notions of an independentflowof time and of an action occurrence are not central to their underlying ontology. In [13] Gelfond and Lifschitz ....

....Lifschitz s Language A [13] are not narrative based. This is not to say that they cannot be extended to deal with narrative information (see for example [27] 25] or [21] But the notions of an independentflowof time and of an action occurrence are not central to their underlying ontology. In [13], Gelfond and Lifschitz proposed a particular methodology for research into reasoning about action. The authors introduced the Language A as a simple declarative language for describing actions , and suggested that, by describing general translation procedures from A domains into other ....

[Article contains additional citation context not shown here]

Michael Gelfond and Vladimir Lifschitz, Representing Actions in Extended Logic Programming, Proceedings of the JointInternational Conference and 39 Symposium on Logic Programming, ed. Krzysztof Apt, MIT Press, page 560, 1992.

....a formalism in which not only all possible domains but also facts describing changes to a domain specification can be expressed. Non monotonic reasoning [38] has been found necessary for dealing with this problem in AI but has proven extremely difficult to formalize [84] Gelfond and Lifschitz [35] identified a simple class of domains, a class of finite state systems, which they describe using a language called A for testing various approaches to formalizing non monotonic reasoning. We show how the semantics of A may be mechanized in the Boyer Moore logic, a first order logic, by ....

....[77, 80, 61] have been proposed for formalizing the needed nonmonotonic reasoning. The ideas behind the problem of specification modification and the need for non monotonic reasoning are best illustrated using the class of domains (finite state systems) proposed by Gelfond and Lifschitz [35] for testing non monotonic formalisms. The class of domains under consideration have the following properties: 1. The states of the system are given by the propositional values of a finite number of boolean variables or fluents. 2. Actions are not parameterized and are assumed to be executable in ....

[Article contains additional citation context not shown here]

Michael Gelfond and Vladimir Lifschitz. Representing actions in extended logic programming. In Krzysztof Apt, editor, Proc. Joint Int'l Conf. and Symp. on Logic Programming, pages 559--573, 1992.

....to information about e ects of later actions over e ects of earlier actions; 2) to develop an argumentation based computational model for this type of reasoning in logic programming goal driven style. 1 Introduction The idea of specialised action description languages was rst introduced in [7, 8] (and here exempli ed by the Language A) with the aim that such languages could serve as speci cations for theories of action and change written in di erent, general purpose or computation oriented formalisms. One such language is the Language E [10] designed to describe domains involving ....

.... is the Language E [10] designed to describe domains involving narrative information, i.e. information about actual occurrences of actions, using a basic ontology of actions, uents and time points inspired by the Event Calculus [12, 13] This paper contributes to the research agenda suggested in [7, 8] by showing how a signi cant class of E domains may be translated into the argumentation framework of Logic Programming without Negation as Failure (LPwNF) 4] and thus be given an argumentation based, goal driven proof theory. LPwNF uses a priority relation between potentially con icting or ....

M. Gelfond and V. Lifschitz. Representing Actions in Extended Logic Programming. JICSLP'92, 560, MIT Press.

....proves that this is possible and does not lead to intricacies. However, the connections with linear logic will be explored in future work. The concept of resource handling is closely related to the notions of action and change, which have recently been the subjects of many researches: see e.g. [8, 10, 11, 13, 14, 19, 20, 21, 22, 23, 25]. Our work differs from them as follows. The language AbstrAct [25] specifies the activities of systems by action rules characterizing agents capable of performing actions that operate on a global shared data space. A feature of AbstrAct is that it distinguishes between actions to induce state ....

....of resources is expressed either by default or by means of non destructive pre conditions. The article [21] has proposed to use nonmonotonic inference rules and a default law of inertia to tackle the frame problem. The paper [23] has employed linear logic to describe actions and changes. The paper [10] has used extended logic programs with both classical negation and negation as failure for that purpose. The paper [8] has used normal logic programs with abduction. Our work differs from all of them by using a slight extension of Horn clause programs involving no negation and remaining in the ....

M. Gelfond and V. Lifschitz. Representing Actions in Extended Logic Programming. In K.R. Apt, editor, Proc. Joint International Conference and Symposium on Logic Programming, pages 559--573, Washington, USA, November 1992. The MIT Press.

....Pereira Carlos Viegas Dam asio Jos e J ulio Alferes CRIA Uninova and DCS, U. Nova de Lisboa 2825 Monte da Caparica, Portugal (flmp,cd,jjag fct.unl.pt) 1 Introduction Recent approaches make use of logic programming (LP) and in particular LP with explicit negation (extended logic programming XLP) [13, 8, 9], to solve and represent nonmonotonic reasoning problems [20, 17] The aim of this paper is to enlarge in an unified way the scope of XLP applications to diagnosis, and to declarative debugging. The expressive power of XLP to do so is attained by allowing would be contradictory programs to be ....

M. Gelfond and V. Lifschitz. Representing actions in extended logic programming. In K. Apt, editor, Proc. IJCSLP'92. MIT Press, 1992.

.... Fluents framework [36] where a series of action occurrences are captured as a schedule) and Kowalski and Sergot s Event Calculus [24] On the other hand, formalisms such as McCarthy and Hayes Situation Calculus [29] Dynamic Logics (see for example [18] and Gelfond and Lifschitz s Language A [16] are not narrative based. This is not to say that they cannot be extended to deal with narrative information (see for example [34] 31] or [26] But the notions of an independent flow of time and of an action occurrence are not central to their underlying ontology. In [16] and [17] Gelfond ....

....Language A [16] are not narrative based. This is not to say that they cannot be extended to deal with narrative information (see for example [34] 31] or [26] But the notions of an independent flow of time and of an action occurrence are not central to their underlying ontology. In [16] and [17] Gelfond and Lifschitz proposed a particular methodology for research into reasoning about action. The authors introduced the Language A as a simple declarative language for describing actions , and suggested that, by describing general translation procedures from A domains into other ....

[Article contains additional citation context not shown here]

Michael Gelfond and Vladimir Lifschitz, Representing Actions in Extended Logic Programming, Proceedings of the Joint International Conference and Symposium on Logic Programming, ed. Krzysztof Apt, MIT Press, page 560, 1992.

....state of the world is used to predict the future state that results from the execution of a given sequence of actions. More complex reasoning tasks may also involve backwards reasoning, or reasoning from the future to the past. Additional rules needed for this purpose were introduced in [ Gelfond and Lifschitz, 1992 ] With these rules added, the program is not acyclic anymore; hence the need to use query evaluation procedures with better termination properties than Prolog, such as SLG. There are three reasons why a program written as proposed in [ Gelfond and Lifschitz, 1992 ] cannot be directly ....

....purpose were introduced in [ Gelfond and Lifschitz, 1992 ] With these rules added, the program is not acyclic anymore; hence the need to use query evaluation procedures with better termination properties than Prolog, such as SLG. There are three reasons why a program written as proposed in [ Gelfond and Lifschitz, 1992 ] cannot be directly submitted to SLG for execution. First, these programs are extended, that is, they use classical negation alongside negation as failure; SLG does not know about classical negation. Second, in the presence of rules for backwards reasoning, even the sophisticated search method ....

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Michael Gelfond and Vladimir Lifschitz. Representing actions in extended logic programming. In Krzysztof Apt, editor, Proc. Joint Int'l Conf. and Symp. on Logic Programming, pages 559--573, 1992.

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Gelfond, M. and Lifschitz, V., "Representing Actions in Extended Logic Programming," Proc. Joint Int. Conf-Symp on Logic Programming, 1992.

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