Chapter 7. RDFS-Plus

RDFS provides a very limited set of inference capabilities that, as we have seen, have considerable utility in a Semantic Web setting for merging information from multiple sources. In this chapter, we take the first step toward the Web Ontology Language OWL, in which more elaborate constraints on how information is to be merged can be specified. We have selected a particular set of OWL constructs to present at this stage. This set was selected to satisfy a number of goals:

• Pedagogically, these constructs constitute a gentle addition to the constructs that are already familiar from RDFS, increasing the power of the language without making a large conceptual leap from RDFS.

• Practically, we have found that this set of OWL constructs has considerable utility in the information integration projects we have done. In fact, it is much easier to find and describe case studies using RDFS plus this set of OWL constructs than it is to find case studies that use RDFS by itself.

• Computationally, this subset of OWL can be implemented using a wide variety of inferencing technologies, lessening the dependency between the Semantic Web and any particular technology.