Charles Elkan. Reasoning about action in first-order logic. In Proc. 1992.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....of reasoning but focusses on the use of an unfolding partial evaluation procedure for integrity checking of database updates. The question whether such an unfolding procedure is of practical use for general problem solving in temporal domains is not dealt with in Dung s paper. 7 Discussion In [12], a First Order Logic solution to the frame problem was proposed. 30] uses the same type of theory to formalise database evolution. This type of theory is a form of situation calculus which shows a strong similarity with the completion of a program D. Result=2 is replaced by do=2. Instead of ....

C. Elkan. Reasoning about Action in First-Order Logic. In Proc. of the CSCSI92, 1992.

....2. 4 Actually this general problem shows a striking similarity to the necessity of distinguishing caused from unmotivated indirect effects as part of the broader Ramification Problem. Research in this context has recently produced several successful approaches which appeal to causality (e.g. Elkan, 1992; Geffner and Pearl, 1992; Lin, 1995; McCain and Turner, 1995; Thielscher, 1997 ] In Section 4, we show how these results can be exploited to successfully address the problem considered in the present paper. The conceptually crucial step towards this end is to identify event occurrences with ....

.... and Hertzberg, 1993; Kartha and Lifschitz, 1994; Sandewall, 1995 ] but it just as well turned out applicable to a certain extent only [ Thielscher, 1997 ] Recent research results on the Ramification Problem show how this limitations can be overcome by directly appealing to causality (e.g. Elkan, 1992; Geffner and Pearl, 1992; Lin, 1995; McCain and Turner, 1995; Thielscher, 1997 ] In the following, we exploit these results for the development of a causality based solution to the problem of deriving the wrong event occurrences. In order that this can be done, we first have to resolve an ....

Charles Elkan. Reasoning about action in first-order logic. In Proceedings of the Conference of the Canadian Society for Computational Studies of Intelligence (CSCSI), pages 221--227, Vancouver, Canada, May 1992. Morgan Kaufmann.

....can be represented. Sandewall shows that this formalism is able to handle many examples on which chronological minimization fails to produce intuitively correct results. Recently, some (closely related) first order methods of reasoning about action [Reiter, 1991; Pednault, 1989; Schubert, 1990; Elkan, 1992; Davis, 1991] have appeared in the literature. Since we will have occasion to discuss these methods in detail later, we will postpone the discussion of these. 2.7 Notation In formulae, constants are denoted by any sequence of characters starting with an uppercase letter (e.g. InGarage) and ....

....translation, in which case we might try to modify the idea so that we again obtain soundness and completeness. As an example of the first kind of outcome, we can easily prove a theorem of the same form as Theorem 3. 2 for the first order scheme (similar to that of Pednault and Reiter) proposed by Elkan [1992]. An example of the second kind of outcome, the translation from A into the language of logic programs presented in [Gelfond and Lifschitz, 1993] is incomplete. Turner [1994] exhibits a sound and complete translation from A into the language of disjunctive logic programs. As noted before, the ....

Charles Elkan. Reasoning about action in first-order logic. In Proceedings of the Ninth Biennial Conference of the Canadian Society for Computational Studies of Intelligence (CSCSI'92), Vancouver, Canada. Morgan Kaufmann, 1992.

....representation problems that occur in formalisms for reasoning about actions and change. Examples for this use of causal reasoning are approaches to the Frame Problem, e.g. Lifschitz 1987) the Qualification Problem, e.g. Thielscher 1996) and, in particular, the Ramification Problem, e.g. (Elkan 1992; Geffner Pearl 1992; Lin 1995; McCain Turner 1995; Thielscher 1997) Each of these formalisms, however, employs an individual concept of causality, tailored to the underlying framework. In other words, causality is used merely as a tool for reasoning about actions and is thus not in the focus ....

Elkan, C. 1992. Reasoning about action in first-order logic. In Proceedings of the Conference of the Canadian Society for Computational Studies of Intelligence (CSCSI), 221--227. Vancouver, Canada: Morgan Kaufmann.

....A causal relationship is an expression of the form causes if Phi where Phi is a fluent formula and and are fluent literals. 9 This example has been suggested by Erik Sandewall (personal communication) 10 Related approaches to the ramification problem have been developed in, e.g. [Elkan, 1992; Geffner, 1992; Brewka and Hertzberg, 1993; Lin, 1995; McCain and Turner, 1995] See [Thielscher, 1997] for a detailed comparison. 7 The intended reading is the following: Under condition Phi , the (previously obtained, direct or indirect) effect triggers the indirect effect . e.g. the ....

Charles Elkan. Reasoning about action in first-order logic. In Proceedings of the Conference of the Canadian Society for Computational Studies of Intelligence (CSCSI), pages 221--227, Vancouver, Canada, May 1992. Morgan Kaufmann.

....of actions were recognized by Ginsberg and Smith [1988b] Lifschitz [1990] and Lin and Reiter [1995] Several authors have proposed to overcome these difficulties by replacing state constraints by representations of causal knowledge of one kind or another. These include Geffner [1989,1990] Elkan [1992], Brewka and Hertzberg [1993] Baral [1995] Lin [1995] McCain and Turner [1995] and Thielscher [1995a,1996] The representation of causal knowledge presented in this dissertation is a simplification and generalization of the proposal of McCain and Turner. 1.2 What Kind of Causal Knowledge In ....

....the effects of actions) in classical logic. This is possible if it is assumed that the effect axioms describe all of the effects of the actions. Reiter builds on Pednault s proposal but achieves additional parsimony by quantifying over actions, as recommended by Haas [1987] and Schubert [1990] Elkan [1992] proposes an approach to formalizing action domains directly in classical logic. The reasoning formalized in classical logic is monotonic in the sense that acquiring new information can only lead to additional conclusions being drawn, not to earlier conclusions being retracted. Commonsense ....

Charles Elkan. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence, 1992.

....is represented in the form of state constraints, which have been traditionally used for this purpose. Recently, many authors have argued that state constraints are inadequate for representing background knowledge in action domains, because they do not adequately represent causal relations [Gef90, Elk92, Bar95, Lin95, MT95b, Thi95]. Accordingly, AC includes propositions that express static causal laws of the following kind: if a fluent formula OE is caused to be true, then a fluent formula is caused to be true. From such a causal law it follows that, in the action domain being described, one can make true by making OE ....

Charles Elkan. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence, 1992.

....of the intuitions behind our solution to the frame and ramification problems have also appeared in earlier work. Reiter s solution to the frame problem (Reiter 1991) relies on a causal completion assumption and amounts to almost the same form of successor state axioms as obtained in our paper. Elkan (Elkan 1992) specifies indirect effects of actions by providing a complete description of how the truth value of a particular fluent might be caused (i.e. become true) or canceled (i.e. become false) Fixed point constructions have appeared in (Thielscher 1996; McCain Turner 1997) Lin (Lin 1995) have ....

Elkan, C. 1992. Reasoning about actions in first order logic. In Proc. of the Conference of the Canadian Society for Computational Studies of Intelligence.

....of actions are generated. Not always are all computed chains of indirect effects equally likely to happen in reality. The causal lag between some particular indirect effect and its triggering cause may generally be shorter than the causal 4 Most of today s approaches are of this kind, e.g. [Elkan, 1992, McCain and Turner, 1995, Lin, 1995, Shanahan, 1997, Kakas and Miller, 1997] 9 lag between another particular effect and its cause. One approach to this problem is to introduce an explicit notion of time, namely, in specifying the exact delay between the occurrence of an effect and its cause. ....

Charles Elkan. Reasoning about action in first-order logic. In Proceedings of the Conference of the Canadian Society for Computational Studies of Intelligence (CSCSI), pages 221--227, Vancouver, Canada, May 1992. Morgan Kaufmann.

....killing him, it does not follow from this that you can bring Fred back to life by making him walk. Recently, a number of researchers have argued that state constraints are inadequate for representing background knowledge in action domains, because they do not adequately represent causal relations [Gef90, Elk92, BH93, Bar95, Lin95, MT95b, Thi95a, Gus96]. In this dissertation we explore the use of static causal laws of the kind introduced by McCain and Turner in [MT95b] if a fluent formula OE is caused to be true, then a fluent formula is also caused to be true. From such a causal law it follows that one can make true by making OE true. ....

....Any correct solution, taken as a whole, will be nonmonotonic, even if the end product is expressed in a monotonic formalism. Of course this holds, presumptively, for less systematic proposals, which discuss frame axioms for some examples without specifying a general method for generating them [Haa87, Elk92]. Thus the so called monotonic approaches are conceptually similar to the more clearly nonmonotonic 4 In Chapter 3.5 we discuss in some detail their default theory for the Yale Shooting domain. approaches which employ variants of circumscription, autoepistemic logic, default logic and logic ....

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Charles Elkan. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence, 1992.

....and the frame axioms generated by the process outlined in the previous section. We can now prove a theorem about R(D) exactly similar to Theorem 1. Theorem 2 Let D be any finite, consistent domain and let R(D) be defined as before. For any v proposition ff, R(D) j= R(ff) D entails ff. In [ Elkan, 1992 ] Elkan proposed a similar scheme for reasoning about action. We can easily prove a theorem of the same form as Theorem 2 for this scheme also. 5 Translation into Circumscriptive Scheme In this section we will propose a translation into a circumscriptive scheme, based on the method of [ Baker, ....

Charles Elkan. Reasoning about action in first-order logic. In Proceedings of the Ninth Biennial Conference of the Canadian Society for Computational Studies of Intelligence (CSCSI'92), Vancouver, Canada. Morgan Kaufmann, 1992.

....these, so it is not surprising that background knowledge in the form of state constraints should prove to be inadequate. In the recent literature on reasoning about 1 A similar proposal by Lin [1995] appears in these proceedings. action, the inadequacy of state constraints has been observed by Elkan [1992] and by Brewka and Hertzberg [1993] The central problem addressed in this paper is that of properly defining the set of possible next states after performing an action, given specific direct effects and background knowledge in the form of causal laws. 2 For the standard framework in which ....

Charles Elkan. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence, 1992.

....Reiter (1994) A number of authors have proposed to overcome these difficulties by replacing state constraints by representations of 0 Copyright c fl1997, American Association for Artificial Intelligence (www.aaai.org) All rights reserved. causal knowledge of one kind or another (Geffner 1990; Elkan 1992; Brewka Hertzberg 1993; Baral 1995; Lin 1995; McCain Turner 1995; Thielscher 1995) In this paper, we define a mathematically simple language for expressing causal knowledge and describe a general approach to formalizing action domains in it. What Kind of Causal Knowledge Suppose Gamma is ....

Elkan, C. 1992. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence.

....in the form of state constraints, which have been traditionally used for this purpose. Recently, many authors have argued that state constraints are inadequate for representing background knowledge in action domains, because they do not adequately represent causal relations (Geffner 1990; Elkan 1992; Brewka Hertzberg 1993; Baral 1995; Lin 1995; McCain Turner 1995; Thielscher 1995) Accordingly, AC includes propositions that express static causal laws of the following kind: in the action domain being described, one can make a fluent formula true by making a fluent formula OE true. In ....

Elkan, C. 1992. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence.

....of the situation calculus [ McCarthy and Hayes, 1969 ] we will need to distinguish between proposals of several kinds, differing by the choice of the underlying logic. Some of them combine the situation calculus with classical logic (for instance, Schubert, 1990 ] Reiter, 1991 ] Elkan, 1992 ] some with logic programming (for instance, Eshghi and Kowalski, 1989 ] Evans, 1989 ] Apt and Bezem, 1990 ] some with circumscription (for instance, Haugh, 1987 ] Lifschitz, 1987 ] Baker, 1989 ] or with other nonmonotonic formalisms (for instance, Morris, 1988 ] and ....

.... constraint (9) stands for causes s ff :ff: 12) In the next section we show that this translation faithfully represents the semantics of the language DL irq (Proposition 1) The idea of a static causal law, in relation to the ramification problem, was developed in [ Geffner, 1990 ] Elkan, 1992 ] Brewka and Hertzberg, 1993 ] Baral, 1995 ] Lin, 1995 ] McCain and Turner, 1995 ] Thielscher, 1995 ] and [ Turner, 1997 ] More recent research was described in the talks given by some of these authors at the workshop on causality held at the University of Texas at Austin in ....

Charles Elkan. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence, 1992.

....these, so it is not surprising that background knowledge in the form of state constraints should prove to be inadequate. In the recent literature on reasoning about 1 A similar proposal by Lin [1995] appears in these proceedings. action, the inadequacy of state constraints has been observed by Elkan [1992] and by Brewka and Hertzberg [1993] The central problem addressed in this paper is that of properly defining the set of possible next states after performing an action, given specific direct effects and background knowledge in the form of causal laws. 2 For the standard framework in which ....

Charles Elkan. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence, 1992.

....causation, so can only represent the direct effects of actions. In fact, both of the causation predicates in [ Lifschitz, 1987 ] and in [ Haugh, 1987 ] take an action but no state argument, and both of the efforts have difficulties handling the ramification problem. Similar remarks apply to [ Elkan, 1992 ] as well despite the fact that the causation predicate there has a state argument. This is because the causation predicate in [ Elkan, 1992 ] continues to have an action argument, and the state argument is introduced only to help expressing complex preconditions. Whereas we treat causality as a ....

....Haugh, 1987 ] take an action but no state argument, and both of the efforts have difficulties handling the ramification problem. Similar remarks apply to [ Elkan, 1992 ] as well despite the fact that the causation predicate there has a state argument. This is because the causation predicate in [ Elkan, 1992 ] continues to have an action argument, and the state argument is introduced only to help expressing complex preconditions. Whereas we treat causality as a predicate, Geffner [ 1990 ] and McCain and Turner [ 1995 ] treat it as modal operators. Nonetheless, it seems that this work and that of [ ....

Charles Elkan. Reasoning about action in first-order logic. In Proc. of the 1992 Canadian Conf. on Artificial Intelligence, 1992.

....Actually this general problem shows a striking similarity to the necessity of distinguishing caused from unmotivated indirect effects as part of the broader Ramification Problem. Research in this context has recently produced several successful approaches which appeal to causality (e.g. Elkan, 1992; Geffner and Pearl, 1992; Lin, 1995; McCain and Turner, 1995; Thielscher, 1997 ] In Section 4, we show how these results can be exploited to successfully address the problem considered in the present paper. The conceptually crucial step towards this end is to identify event occurrences with ....

.... and Hertzberg, 1993; Kartha and Lifschitz, 1994; Sandewall, 1995 ] but it just as well turned out applicable to a certain extent only [ Thielscher, 1997 ] Recent research results on the Ramification Problem show how this limitations can be overcome by directly appealing to causality (e.g. Elkan, 1992; Geffner and Pearl, 1992; Lin, 1995; McCain and Turner, 1995; Thielscher, 1997 ] In the following, we exploit these results for the development of a causality based solution to the problem of deriving the wrong event occurrences. In order that this can be done, we first have to resolve an ....

C. Elkan. Reasoning about action in first-order logic. In Proceedings of the Conference of the Canadian Society for Computational Studies of Intelligence (CSCSI), pages 221--227, Vancouver, Canada, May 1992. Morgan Kaufmann.

.... is replaced by Result(s) i.e. which no longer depends on the execution of some action Other promising directions are the adaption of resource oriented approaches to reasoning about actions and change [ Gro e et al. 1992 ] dynamic logic [ Harel, 1984 ] or a first order encoding following [ Elkan, 1992 ] Last but not least, though in its current state it covers neither the static momentary distinction nor specificity or nondeterminism, the modal logic approach [ Gro e, 1994 ] should be a candidate worth being considered since 7 Note that we are supposed to remove the set sf from ....

C. Elkan. Reasoning about Action in FirstOrder Logic. In Proc. of the Conf. of the Canadian Society for Computational Studies of Intell., Vanvouver, Canada, May 1992. Morgan Kaufmann.

....checks a downloaded applet to ensure it uses authorized resources on the machine receiving the download. Charles Elkan has shown how efficient specialized algorithms could verify logically whether the accesses and updates requested by different users of a database system could possibly interfere [46]. An important advantage of this approach to security is that it can be built on top of existing software for implementing accesses and updates, without requiring any internal modifications of that software. This is work in collaboration with our security group. G.3.5 SCIENTIFIC METACOMPUTING ....

C. Elkan, "Reasoning about Action in First-Order Logic," In Proc. of the 9th Biennial Conf. of the Canadian Society for Computational Studies of Intelligence (CSCSI'92). Vancouver, May 1992. Morgan Kaufmann Publishers.

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Charles Elkan. Reasoning about action in first-order logic. In Proc. 1992.

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C. Elkan. Reasoning about action in first order logic. Proceedings of the Conference of the Canadian Society for Comptutational Studies in Intelligence (CSCSI), pp 221-227, Vancouver, May 1992.

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C. Elkan. Reasoning about action in first order logic. In Proceedings of the Conference of the Canadian Society for Comptutational Studies of Intelligence (CSCSI), pages 221-227, Vancouver, Canada, May 19

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C. Elkan. Reasoning about action in first order logic. In Proceedings of the Conference of the Canadian Society for Comptutational Studies of Intelligence (CSCSI), pages 221-227, Vancouver, Canada, May 19

No context found.

C. Elkan. Reasoning about Action in FirstOrder Logic. In Proc. of the Conf. of the Canadian Society for Computational Studies of Intell., Vanvouver, Canada, May 1992. Morgan Kaufmann.

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