Abox

In Computer Science, an ABox is an "assertion component"—a fact associated with a terminological vocabulary within a knowledge base.

The terms ABox and TBox are used to describe two different types of statements in ontologies. TBox statements describe a system in terms of controlled vocabularies, for example, a set of classes and properties. ABox are TBox-compliant statements about that vocabulary.

TBox statements are sometimes associated with object-oriented classes and ABox statements associated with instances of those classes.

Together ABox and TBox statements make up a knowledge base.

Examples of ABox and TBox statements

ABox statements typically have the form:

 A is an instance of B

or

 John is a Person

This should be contrasted with TBox statements or (statements) about terminology such as:

 All Students are Persons

or

 There are two types of Persons: Students and Teachers

TBox statements tend to be more permanent within a knowledge base and tend to be stored in a data model or a metadata registry. In contrast, ABox statements are much more dynamic in nature and tend to be stored as instance data within transactional systems within databases.

See also

• TBox
• Description Logic#Modeling in Description Logics
• metadata
• Web Ontology Language