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CARIN: A Representation Language Combining Horn Rules and Description Logics
, 1996
"... . We describe CARIN, a novel family of representation languages, which integrate the expressive power of Horn rules and of description logics. We address the key issue in designing such a language, namely, providing a sound and complete inference procedure. We identify existential entailment as a c ..."
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Cited by 104 (1 self)
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. We describe CARIN, a novel family of representation languages, which integrate the expressive power of Horn rules and of description logics. We address the key issue in designing such a language, namely, providing a sound and complete inference procedure. We identify existential entailment as a core problem in reasoning in CARIN, and describe an existential entailment algorithm for CARIN languages whose description logic component is ALCNR. This algorithm entails several important results for reasoning in CARIN, most notably: (1) a sound and complete inference procedure for non recursive CARINALCNR, and (2) an algorithm for determining rule subsumption over ALCNR. 1 Introduction Horn rule languages have formed the basis for many Artificial Intelligence application languages because their expressive power is sufficient for many applications, and they have good computational properties. One of the significant limitations of Horn rules is that they are not expressive enough to mod...
Records for Logic Programming
 Journal of Logic Programming
, 1994
"... CFT is a new constraint system providing records as logical data structure for constraint (logic) programming. It can be seen as a generalization of the rational tree system employed in Prolog II, where finergrained constraints are used, and where subtrees are identified by keywords rather than by ..."
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Cited by 101 (19 self)
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CFT is a new constraint system providing records as logical data structure for constraint (logic) programming. It can be seen as a generalization of the rational tree system employed in Prolog II, where finergrained constraints are used, and where subtrees are identified by keywords rather than by position. CFT is defined by a firstorder structure consisting of socalled feature trees. Feature trees generalize the ordinary trees corresponding to firstorder terms by having their edges labeled with field names called features. The mathematical semantics given by the feature tree structure is complemented with a logical semantics given by five axiom schemes, which we conjecture to comprise a complete axiomatization of the feature tree structure. We present a decision method for CFT, which decides entailment / disentailment between possibly existentially quantified constraints. Since CFT satisfies the independence property, our decision method can also be employed for checking the sat...
A Temporal Description Logic for Reasoning about Actions and Plans
 Journal of Artificial Intelligence Research
, 1998
"... A class of intervalbased temporal languages for uniformly representing and reasoning about actions and plans is presented. Actions are represented by describing what is true while the action itself is occurring, and plans are constructed by temporally relating actions and world states. The tempo ..."
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Cited by 100 (20 self)
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A class of intervalbased temporal languages for uniformly representing and reasoning about actions and plans is presented. Actions are represented by describing what is true while the action itself is occurring, and plans are constructed by temporally relating actions and world states. The temporal languages are members of the family of Description Logics, which are characterized by high expressivity combined with good computational properties. The subsumption problem for a class of temporal Description Logics is investigated and sound and complete decision procedures are given. The basic language TLF is considered #rst: it is the composition of a temporal logic TL # able to express interval temporal networks # together with the nontemporal logic F # a Feature Description Logic. It is proven that subsumption in this language is an NPcomplete problem. Then it is shown how to reason with the more expressive languages TLUFU and TLALCF . The former adds disjunction both at...
Towards a Declarative Query and Transformation Language for XML and Semistructured Data: Simulation Unification
, 2002
"... The growing importance of XML as a data interchange standard demands languages for data querying and transformation. Since the mid 90es, several such languages have been proposed that are inspired from functional languages (such as XSLT [1]) and/or database query languages (such as XQuery [2]). ..."
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Cited by 90 (37 self)
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The growing importance of XML as a data interchange standard demands languages for data querying and transformation. Since the mid 90es, several such languages have been proposed that are inspired from functional languages (such as XSLT [1]) and/or database query languages (such as XQuery [2]). This paper addresses applying logic programming concepts and techniques to designing a declarative, rulebased query and transformation language for XML and semistructured data.
A Feature Logic with Subsorts
 LILOG Report 33, IWBS, IBM Deutschland
, 1992
"... This paper presents a set description logic with subsorts, feature selection (the inverse of unary function application), agreement, intersection, union and complement. We define a model theoretic open world semantics and show that sorted feature structures constitute a canonical model, that is, ..."
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Cited by 81 (4 self)
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This paper presents a set description logic with subsorts, feature selection (the inverse of unary function application), agreement, intersection, union and complement. We define a model theoretic open world semantics and show that sorted feature structures constitute a canonical model, that is, without loss of generality subsumption and consistency of set descriptions can be considered with respect to feature structures only. We show that deciding consistency of set descriptions is an NPcomplete problem. To appear in: J. Wedekind and C. Rohrer (eds.), Unification in Grammar. The MIT Press, 1992 This text is a minor revision of LILOG Report 33, May 1988, IBM Deutschland, IWBS, Postfach 800880, 7000 Stuttgart 80, Germany. The research reported here has been done while the author was with IBM Deutschland. The author's article [23] is a more recent work on feature logics. 1 1 Introduction This paper presents a set description logic that generalizes and integrates formalisms...
A Featurebased Constraint System for Logic Programming with Entailment
, 1992
"... This paper presents the constraint system FT, which we feel is an intriguing alternative to Herbrand both theoretically and practically. As does Herbrand, FT provides a universal data structure based on trees. However, the trees of FT (called feature trees) are more general than the trees of Herbran ..."
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Cited by 72 (20 self)
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This paper presents the constraint system FT, which we feel is an intriguing alternative to Herbrand both theoretically and practically. As does Herbrand, FT provides a universal data structure based on trees. However, the trees of FT (called feature trees) are more general than the trees of Herbrand (called constructor trees), and the constraints of FT are finer grained and of different expressivity. The basic notion of FT are functional attributes called features, which provide for recordlike descriptions of data avoiding the overspecification intrinsic in Herbrand's constructorbased descriptions. The feature tree structure fixes an algebraic semantics for FT. We will also establish a logical semantics, which is given by three axiom schemes fixing the firstorder theory FT. FT is a constraint system for logic programming, providing a test for unsatisfiability, and a test for entailment between constraints, which is needed for advanced control mechanisms. The two major technical con...
Logic Programming over Polymorphically OrderSorted Types
, 1989
"... This thesis presents the foundations for relational logic programming over polymorphically ordersorted data types. This type discipline combines the notion of parametric polymorphism, which has been developed for higherorder functional programming, with the notion of ordersorted typing, which ha ..."
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Cited by 59 (0 self)
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This thesis presents the foundations for relational logic programming over polymorphically ordersorted data types. This type discipline combines the notion of parametric polymorphism, which has been developed for higherorder functional programming, with the notion of ordersorted typing, which has been developed for equational firstorder specification and programming. Polymorphically ordersorted types are obtained as canonical models of a class of specifications in a suitable logic accommodating sort functions. Algorithms for constraint solving, type checking and type inference are given and proven correct.
A Modal Perspective on the Computational Complexity of Attribute Value Grammar
, 1992
"... Many of the formalisms; used in Attribute Value grammar are notational variants of languages of propositional modal logic,. and testing whether two Attribute Value descriptions unify amounts to testing for modal satisfiability. In this paper we put this. observation to work. We study the complexit ..."
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Cited by 49 (7 self)
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Many of the formalisms; used in Attribute Value grammar are notational variants of languages of propositional modal logic,. and testing whether two Attribute Value descriptions unify amounts to testing for modal satisfiability. In this paper we put this. observation to work. We study the complexity of the satisfiability problem for nine modal languages which mirror different aspects of AVS description formalisms, including the ability to express reeintrancy, the ability to express generalisations, and the ability to express recursive constraints. Two mail techniques axe used: either Kripke models with desirable properties are constructed, or modalities are used to simulate fragments of Propositional Dynamic Logic. Further possibilities for the application of modal logic in computational linguistics are noted
Default Representation in ConstraintBased Frameworks
 Computational Linguistics
, 1998
"... this paper allows any defaults to be overridden by defaults which are associated with more specific types: thus priority ordering reflects the type hierarchy ordering. (In 6.2, we will mention other possibilities for imposing a priority order on defaults.) Barring criterion 6, all of the above ..."
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Cited by 48 (6 self)
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this paper allows any defaults to be overridden by defaults which are associated with more specific types: thus priority ordering reflects the type hierarchy ordering. (In 6.2, we will mention other possibilities for imposing a priority order on defaults.) Barring criterion 6, all of the above properties are necessary for making default unification behave as much like normal unification as possible, save that (default) information can be overridden. These criteria ensure that the default unification operation has properties familiar from monotonic unification, such as determinacy, the way information is accumulated, the conditions when unification fails, and order independence. Since this guarantees that default unification shares many of the properties of normal unification, a `seamless transition' is possible between the monotonic approach to linguistic analysis supplied by normal unification, and the extension to these analyses provided by supplying default constraints and default unification operating over them. We will justify these assumptions with respect to particular linguistic examples in 4