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FLogic: a higherorder language for reasoning about objects, inheritance, and scheme
, 1997
"... We propose a database logic which accounts in a clean declarative fashion for most of the “objectoriented” features such as object identity, complex objects, inheritance, methods, etc. Furthermore, database schema is part of the object language, which allows the user to browse schema and data using ..."
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Cited by 174 (9 self)
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We propose a database logic which accounts in a clean declarative fashion for most of the “objectoriented” features such as object identity, complex objects, inheritance, methods, etc. Furthermore, database schema is part of the object language, which allows the user to browse schema and data using the same declarative formalism. The proposed logic has a formal semantics and a sound and complete resolutionbased proof procedure, which makes it also computationally attractive.
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 72 (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 69 (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 58 (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.
Order Independent and Persistent Typed Default Unification
 LINGUISTICS AND PHILOSOPHY
, 1999
"... We define an order independent version of default unification on typed feature structures. The operation is ..."
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Cited by 26 (1 self)
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We define an order independent version of default unification on typed feature structures. The operation is
Strategies For Adding Control Information To Declarative Grammars
, 1991
"... Strategies are proposed for combining different kinds of constraints in dcclarative grammars with a detachable layer of control information. The added control information is the basis for parametrized dynamically controlled linguistic deduction, a form of linguistic processing that permits the imple ..."
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Cited by 26 (1 self)
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Strategies are proposed for combining different kinds of constraints in dcclarative grammars with a detachable layer of control information. The added control information is the basis for parametrized dynamically controlled linguistic deduction, a form of linguistic processing that permits the implementation of plausible linguistic performance models without giving up the declarative formulation of linguistic competence. The information can be used by the linguistic processor for ordering the sequence in which conjuncts and disjuncts are processed, for mixing depthfirst and breadthfirst search, for cutting off undesired derivations, and for constraintrelaxation.
Unification of Disjunctive Feature Descriptions
 in: Proceedings of the 26th Annual Meeting of the ACL
, 1988
"... The paper describes a new implementation of feature structures containing disjunctive values, which can be characterized by the following main points: Local representation of embedded disjunctions, avoidance of expansion to disjunctive normal form and of repeated testunifications for checking cons ..."
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Cited by 24 (0 self)
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The paper describes a new implementation of feature structures containing disjunctive values, which can be characterized by the following main points: Local representation of embedded disjunctions, avoidance of expansion to disjunctive normal form and of repeated testunifications for checking consistence. The method is based on a modification of Kasper and Rounds ' calculus of feature descriptions and its correctness therefore is easy to see. It can handle cyclic structures and has been incorporated successfully into an environment for grammar development. 1
A Logical Semantics for ObjectOriented Databases
 In Proc. International SIGMOD Conference on Management of Data
, 1993
"... Although the mathematical foundations of relational databases are very well established, the state of affairs for objectoriented databases is much less satisfactory. We propose a semantic foundation for objectoriented databases based on a simple logic of change called rewriting logic, and a langua ..."
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Cited by 19 (2 self)
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Although the mathematical foundations of relational databases are very well established, the state of affairs for objectoriented databases is much less satisfactory. We propose a semantic foundation for objectoriented databases based on a simple logic of change called rewriting logic, and a language called MaudeLog that is based on that logic. Some key advantages of our approach include its logical nature, its simplicity without any need for higherorder features, the fact that dynamic aspects are directly addressed, the rigorous integration of userdefinable algebraic data types within the framework, the existence of initial models, and the integration of query, update, and programming aspects within a single declarative language. 1 Introduction Although the mathematical foundations of relational databases are very well established, the state of affairs for objectoriented databases is much less satisfactory. This is unfortunate, because objectoriented databases seem to have impor...
A Feature Constraint System for Logic Programming with Entailment
 THEORETICAL COMPUTER SCIENCE
, 1992
"... We introduce a constraint system called FT. This system offers a theoretical and practical alternative to the usual Herbrand system of constraints over constructor trees. Like Herbrand, FT provides a universal data structure based on trees. However, the trees of FT (called feature trees) are more g ..."
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Cited by 16 (1 self)
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We introduce a constraint system called FT. This system offers a theoretical and practical alternative to the usual Herbrand system of constraints over constructor trees. Like Herbrand, FT provides a universal data structure based on trees. However, the trees of FT (called feature trees) are more general than the constructor trees of Herbrand, and the constraints of FT are of finer grain and of different expressiveness. The essential novelty of FT is provided by functional attributes called features which allow representing data as extensible records, a more flexible way than that offered by Herbrand's fixed arity constructors. The feature tree structure determines an algebraic semantics for FT. We establish a logical semantics thanks to three axiom schemes presenting the firstorder theory FT. We propose using FT as a constraint system for logic programming. We provide a test for constraint unsatisfiability, and a test for constraint entailment. The former corresponds to unification ...