Michael Kifer

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We propose a novel formalism, called <italic>Frame Logic</italic> (abbr., F-logic), that accounts in a clean and declarative fashion for most of the structural aspects of object-oriented and frame-based languages. These features include object identity, complex objects, inheritance, polymorphic types, query methods, encapsulation, and others. In a sense,(More)
Annotated logics were introduced in 43] and later studied in 5, 7, 31, 32]. In 31], annotations were extended to allow variables and functions, and it was argued that such logics can be used to provide a formal semantics for rule-based expert systems with uncertainty. In this paper we continue to investigate the power of this approach. First, we introduce a(More)
D We describe a novel logic, called HiLog, and show that it provides a more suitable basis for logic programming than does traditional predicate logic. HiLog has a higher-order syntax and allows arbitrary terms to appear in places where predicates, functions, and atomic formulas occur in predicate calculus. But its semantics is first-order and admits a(More)
The chase algorithm is a fundamental tool for query evaluation and for testing query containment under tuple-generating dependencies (TGDs) and equality-generating dependencies (EGDs). So far, most of the research on this topic has focused on cases where the chase procedure terminates. This paper introduces expressive classes of TGDs defined via syntactic(More)
We propose a database logic which accounts in a clean declarative fashion for most of the &#8220;object-oriented&#8221; 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(More)
An extension of predicate logic, called Transaction Logic, is proposed, which accounts in a clean and declarative fashion for the phenomenon of state changes in logic programs and databases. Transaction Logic has a natural model theory and a sound and complete proof theory, but unlike many other logics, it allows users to program transactions. The semantics(More)
1 Introduction Recent yeara saw several proposals for languages for querying object-oriented databases [2, 3, 4, 5, 13, 6]. None of them, however , captures (or even attempts to deal with) all the aspects of the object-oriented model. In this paper, we present a new query language, henceforth referred to as XSQL, that incorporates fea tures not found in(More)
Most known computational approaches to reasoning have problems when facing inconsistency, so they assume that a given logical system is consistent. Unfortunately, the latter is difficult to verify and very often is not true. It may happen that addition of data to a large system makes it inconsistent, and hence destroys the vast amount of meaningful(More)
This paper presents an overview of Transaction Logic|a new formalism recently introduced in 11, 12] and designed to deal with the phenomenon of state changes in logic programming, databases, and AI. Transaction Logic has a natural model theory and a sound and complete proof theory. Unlike many other logics, however, it is suitable for programming procedures(More)