What does OWL add that RDF-schema doesn ?
A. Owl extends RDFS to allow for the expression of complex relationships between different RDFS classes and of more precise constraints on specific classes and properties. Example of these include: – the means to limit the properties of classes with respect to number and type, – the means to infer that items with various properties are members of a particular class – the means to determine if all members of a class will have a particular property, or if only some of them might – the means to distinguish one-to-one from many-to-one or one-to-many relationships, allowing the “foreign keys” of a database to be represented in an ontology – the means to express relationships between classes defined in different documents across the web, – the means to construct new classes out of the unions, intersections and complements of other classes, and – the means to constrain range and domain to specific class/property combinations. The OWL Guide provides examples of all of these in the area of desc
