SEMANTICS OF PROPERTY INHERITANCE IN A HIERARCHICAL SYSTEM WITH EXPLICIT NEGATION

• Type: Article in International Scientific Journal
• Date: 1991

Authors

DAVID, G (Author) FEUP; PORTO, A (Author) Other

Journal

Title: Lecture Notes in Computer Science

Vol. 541

Pages: 135-150

ISSN: 0302-9743

Publisher: Springer Nature

Indexing

ISI Web of Knowledge - 0 Citations

Other information

Authenticus ID: P-001-R3E

Abstract (EN): The purpose of this paper is to present a first step in a formal study of inheritance systems. The kind of systems considered are those that support overriding (all definitions being taken as defaults) and multiple inheritance. The overriding is based on the explicit statement of negative information. The basic entities are classes and properties. The system is hierarchic because it is made out of classes which are structured as a hierarchy. We consider both the basic case of properties restricted to atomic propositional formulas and their negations, and the extension to properties defined by rules in the Logic Programming style. A formal definition of hierarchic systems is given for which a model-theoretic 3-valued semantics is introduced. This semantics is explicitly stated in terms of sets of individuals. It defines the notion of interpretation, the characterization of models, and what is meant by validity of formulas in such structures. The inheritance mechanism is able to choose from a set of inherited default properties which ones mechanism be overriden in order to guarantee that the local program has a model. The notion of characteristic individuals of classes, introduced in our semantics, turns out to play a clarifying role of the relationship between semantic and syntactic aspects of inheritance systems.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 16