Franz Baader and Bernhard Hollunder. Embedding defaults into terminological knowledge representation formalisms. In Bernhard Nebel, Charles Rich, and William Swartout, editors, KR'92. Principles of Knowledge Representation and Reasoning: Proceedings of the Third International Conference, pages 306--317, San Mateo, California, 1992. Morgan Kaufmann.  Home/Search   Document Details and Download   Summary   Related Articles   Check

.... In addition, the paper briefly presents two The fact that both HAM ALC and FaCT are imple parts of a knowledge representation framework which have been developed based on HAM ALC: i) an implementation of the algorithms for embedding defaults into terminological formalisms presented in [2] and (ii) a Web interface for defining TBoxes (and ABoxes) with an infix syntax (ASCII counterpart of the German Syntax for L A T E X, see below) 2 The Implementation The architecture of HAM ALC explicitly represents the rules for a standard tableau calculus as procedures which operate on ....

....checker provides the basic algorithm for other reasoning services. For instance, default rules can be integrated into a knowledge representation framework. 4. 1 Defaults We implemented a Reiter style default rule system according to the theory and algorithms for computing extensions presented in [2]. Default rules are applied to ABox individuals. With this system, for instance, the famous Nixon example can be declared as follows. Preconditions and conclusions are concepts, justifications are lists of concepts. define default rule nixon as a republican :precondition nixon ....

F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. In B. Nebel, Ch. Rich, and W. Swartout, editors, Third International Conference on Principles of Knowledge Representation, pages 306--317, October 1992.

....McDermott and Jon Doyle, researchers prefer to use its modification proposed in the mid eighties by Bob Moore autoepistemic logic [ 13 ] Literature on default logic has its share of revisionist papers also. Many of them have to do with the use of bound variables in default theories (see [ 1 ] on problems caused by Skolemization) But even quantifier free default logic is rich and useful. It is remarkable how much of the modern 1 research related to default logic refers to Ray Reiter s original publication, and not to any of the ingenious attempts to improve on his definition. 2. In ....

Franz Baader and Bernard Hollunder. Embedding defaults into terminological knowledge representation formalisms. Journal of Automated Reasoning, 14:149--180, 1995.

....logics play a fundamental role in knowledge representation and commonsense reasoning, as well as in the theory of programming languages. 1 The semantic and algorithmic aspects of non monotonic reasoning have been extensively investigated (e.g. see [22, 26, 13, 17, 18, 9, 29, 33, 25] and [30, 27, 3, 4, 7, 35, 1, 2, 31, 36]) On the other hand, the proof theoretic aspects are not yet completely understood. The fundamental papers by Gabbay [14] Makinson [24] and Kraus, Lehmann and Magidor [19] focus their attention on general properties of non monotonic inference, rather than on specific formalisms. In ....

F. Baader, B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. Journal of Automated Reasoning, 14(1):149-180, 1995.

....on whether rules apply, do not apply, or are open, are very useful in explaining the reasoning of KRS to users or in requesting additional information in order to clarify whether open rules apply. The support of default reasoning is another important extension required of description logics (Baader and Hollunder, 1992) and rules with exceptions may be used to provide normal defaults (Reiter, 1980) by assuming that open rules will not fire. However, a prioritization of defaults (Quantz and Royer, 1992; Giordano and Martelli, 1994) is also required since, otherwise, the rules that are allowed to fire as a result ....

Baader, F. and Hollunder, B. (1992). Embedding defaults into terminological knowledge representation formalisms. Proceedings of KR'92: Third International Conference on Principles of Knowledge Representation and Reasoning. pp.306-317. San Mateo, California, Morgan Kauffman.

....in Section 6. Finally, in Section 7 we show that the McCain Turner semantics of causal rules is indeed equivalent to a special case of the semantics proposed in this note. 2 It is known, for instance, that the semantics of open defaults proposed in [Reiter, 1980] leads to serious difficulties [Baader and Hollunder, 1995]. 3 Quantifiers over propositional variables can be always eliminated, although this can make the formula significantly longer. There exists an implementation of a process of eliminating quantifiers over predicate variables based on the ideas of [Ackermann, 1935] ....

Franz Baader and Bernard Hollunder. Embedding defaults into terminological knowledge representation formalisms. Journal of Automated Reasoning, 14:149--180, 1995.

....belief and knowledge of intelligent agents) and time dependent knowledge is only possible in a very restricted way. To allow for the representation of such commonsense knowledge, we have investigated the combination of terminological KR formalisms with modal logics [8] and with default logic [6, 7].In both cases, an appropriate combination is possible without losing decidability of the combined formalism. Symbolic constraints and combination problems We have continued to investigate the problem of combining symbolic constraints systems in a systematic way. An important question in this ....

F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. J. Automated Reasoning, 14:149--180, 1995.

....to characterizing the generating defaults. We will use the notation CnR which stands for the consequence relation induced by a set R of monotonic rules. The rst characterization is based on examining default rules directly. This approach has been presented in several papers [MT93, RS94, BH95] The idea is to project the conditions ful lled by an extension to individual default rules. First, extensions are grounded which means that the corresponding set of generating defaults must be grounded in the following sense. A set of defaults D is grounded in a set formulae W if and only if ....

....Cn Mon(D;F ) W ) is the unique extension of (D; W ) 5 A Decision Method for Default Logic There are already quite a number of decision methods for default reasoning. Methods based on the characterization of extensions in terms of generating defaults (Theorem 4. 1) can be found, e.g. in [MT93, BH95, RS94] There are approaches where default reasoning is reduced into another problem like a truth maintenance problem [JK90] or a constraint satisfaction problem [BED91] An interesting approach to provide proof theory for default reasoning based on sequent calculus is proposed by [Bon96, BO97] ....

F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. Journal of Automated Reasoning, 14:149-180, 1995.

....Anyone interested in research in nonmonotonic feature structures should realize that the issues are very similar to those that arise in attempts to introduce defeasibility into taxonomic logics or classification based knowledge representation systems. See, for instance, Quantz Royer 1992] and [Baader Hollunder 1992]. 4. Applications in phonology Though the phenomena of phonology provide many plausible instances of defeasible reasoning, the opportunities for actually applying nonmonotonic logic to this area of linguistics are limited by the need for preliminary foundational work. Such applications require a ....

....2.6.4 that a lot of my own work in this area is still unpublished because I don t feel that I have been able to think the issues through. In the taxonomic logic community, the desirability of adding defeasibility and classification is somewhat controversial. 69 But see [Quantz Royer 1992] and [Baader Hollunder 1992] for work that explores the issues that arise in this area when nonmonotonicity is added. We discussed the issues that arise from the perspective of unification grammar formalisms in Section 3, above. This research area seems to be problematic because of the proliferation of logical theories of ....

Franz Baader and Bernhard Hollunder. "Embedding defaults into terminological knowledge representation systems." In B. Nebel, C. Rich, and W. Swartout, eds., Principles of knowledge representation and reasoning, Morgan Kaufmann, San Mateo, California, 1992, pp. 306--317.

....get: 2kFl(a) The constraint Fl(a) is consistent with C, iff Not a=tweety. We can derive that all birds can fly if they are not our special friend Tweety. Furthermore we would like to stress that it can be derived that fred can fly and tweety cannot fly. The second example due to Baader Hollunder [1] will again lead to a constrained empty clause where a Skolem constant has to satisfy a certain condition. 8x[Ad(x) 9y(Spouse(x; y) Woman(y) Bachelor(x) Spouse(tom,mary) Woman(mary) Adult(tom) Woman(x)kWoman(x) From the first sentence we get two clauses: Adult(x) Spouse(x;s(x) Bachelor(x) ....

Baader, F. and B. Hollunder (1992) Embedding Defaults into Terminological Knowledge Representation Formalisms, in Principles of Knowledge Representation and Reasoning - Proceedings of the 3rd International Conference, B. Nebel, C. Rich and W. Swartout, eds.

.... [11, 29] and can be easily recognized by looking at recent knowledge representation systems based on concept languages such as [2, 30] Work in this direction has already begun with proposals of extending concept languages to deal with different forms of non monotonic reasoning (see for example [1, 23]) We proposed in [7] to enrich concept languages with an epistemic operator defined in the style of [14, 15, 25] While the main emphasis of that paper was to show that answering queries formulated in the epistemic concept languages can be done by extending the calculus for instance checking ....

Baader, F. and Hollunder, B. Embedding defaults into terminological knowledge representation formalisms. In Proc. of the 3nd Int. Conf. on Principles of Knowledge Representation and Reasoning KR-92, pages 306--317. Morgan Kaufmann, 1992.

....classification, there are some problems, for instance, the zombie path problem [7] the lack of an algorithm, and the computational intractability of the approach. More recent approaches combine classificatory and nonmonotonic reason2 ing by integrating default logic into terminological logics [1] without using specificity for conflict resolution, though or they employ a form of preference semantics [13] We will base our combination of inheritance reasoning and classification on the nonmonotonic inheritance reasoning approach by Padgham [10] which avoids the above mentioned ....

F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. In Nebel et al. [9], pages 306--317.

.... are some attempts to generalize this approach to structured classes, but they work in a very restricted setting, and it is not clear how to obtain more general results in this direction (see, e.g. 15] 3 an integration of Reiter s default logic into a terminological formalism was proposed in [1]. One reason for selecting default logic, out of the wide range of nonmonotonic formalisms, was that Reiter s default rule approach fits well into the philosophy of terminological systems. Most of these systems already provide their users with a form of monotonic forward rules, and it turned out ....

....systems. Most of these systems already provide their users with a form of monotonic forward rules, and it turned out that these rules can be viewed as specific default rules where the justifications are absent. A second pleasant feature of terminological default logic, as introduced in [1], is that it becomes decidable provided that applicability of default rules is restricted to objects explicitly present in the knowledge base. It should be noted that this constraint is also imposed on the monotonic rules in terminological systems. The major drawback which terminological default ....

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F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. In Proceedings of the 3rd International Conference on Knowledge Representation and Reasoning, Cambridge, Mass., 1992. 18

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Franz Baader and Bernhard Hollunder. Embedding defaults into terminological knowledge representation formalisms. In Bernhard Nebel, Charles Rich, and William Swartout, editors, KR'92. Principles of Knowledge Representation and Reasoning: Proceedings of the Third International Conference, pages 306--317, San Mateo, California, 1992. Morgan Kaufmann.

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F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. In B. Nebel, C. Rich, and W. Swartout, editors, KR'92. Principles of Knowledge Representation and Reasoning: Proceedings of the Third International Conference, pages 306--317, San Mateo, California, 1992. Morgan Kaufmann.

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Franz Baader and Bernhard Hollunder. Embedding defaults into terminological knowledge representation formalisms. Technical Report RR-93-20, 1993.

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Franz Baader and Bernard Hollunder. Embedding defaults into terminological knowledge representation formalisms. Journal of Automated Reasoning, 14:149--180, 1995.

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Baader, F., and Hollunder, B. 1992. Embedding defaults into terminological knowledge representation formalisms. In Nebel, B.; Rich, C.; and Swartout, W., eds., Proceedings of the Third International Conference on the Principles of Knowledge Representation and Reasoning, 306--317.

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F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. In B. Nebel, C. Rich, and W. Swartout, editors, Proceedings of the Third International Conference on the Principles of Knowledge Representation and Reasoning, pages 306--317, Cambridge, MA, October 1992.

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F. Baader and B. Hollunder, Embedding Defaults into Terminological Knowledge Representation Formalisms, Journal of Automated Reasoning 14 (1995), 149--180.

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F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. In B. Nebel, C. Rich, and W. Swartout, editors, KR'92. Principles of Knowledge Representation and Reasoning: Proc. of the Third Int. Conf., pages 306--317, San Mateo, California, 1992. Morgan Kaufmann.

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F. Baader and B. Hollunder. Embedding Defaults into Terminological Knowledge Representation Formalisms. Journal of Automated Reasoning 14,1 (1995): 149--180.

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F. Baader and B. Hollunder, Embedding Defaults into Terminological Knowledge Representation Formalisms, Journal of Automated Reasoning 14 (1995), 149-180.

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Franz Baader and Bernhard Hollunder. Embedding defaults into terminological knowledge representation formalisms. In Bernhard Nebel, Charles Rich, and William Swartout, editors, KR'92. Principles of Knowledge Representation and Reasoning: Proceedings of the Third International Conference, pages 306--317, San Mateo, California, 1992. Morgan Kaufmann.

No context found.

Franz Baader and Bernhard Hollunder. Embedding defaults into terminological knowledge representation formalisms. In Bernhard Nebel, Charles Rich, and William Swartout, editors, KR'92. Principles of Knowledge Representation and Reasoning: Proceedings of the Third International Conference, pages 306--317, San Mateo, California, 1992. Morgan Kaufmann.

No context found.

F. Baader and B. Hollunder. Embedding defaults into terminological knowledge representation formalisms. In B. Nebel, C. Rich, and W. Swartout, editors, KR'92. Principles of Knowledge Representation and Reasoning: Proceedings of the Third International Conference, pages 306--317, San Mateo, California, 1992. Morgan Kaufmann.

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