The following was originally a submission by the author to the W3C OWL working group. As the group chose not to include this in their recommendation work (deciding instead to have an OWL profile with far more in it), and as I remain the last (and only) person to edit the content below (others made changes on the wiki page on which it appeared) I see nothing in the submission rules to the RDF Next Steps workshop to prohibit its submission. I have added a title and authorship, and made some minor changes to the original content to make it self-contained outside of the Working Group context.

RDFS 3.0

Jim Hendler, RPI

I believe an important RDF user group is the Web 3.0 Application Developer, who is willing to use a small amount of OWL if it helps, does not often have a classfication/realization problem so are not using DL reasoners, and care about scaling from a computational (rather than formal) view - i.e. being able to do map/reduce parallelism on the feature set would be a valuable plus.

One name that has been suggested for this is "RDFS 3.0" as it would be the third update of RDFS and it would resonate with being a language of use to the "Web 3.0" developer community.

Requirements

1. - is an extension of RDFS but a subset of OWL Lite vocabulary
2. - can have a clean operational semantics defined via a axiomatic specification
3. - if it is closely tied to a particular formalism, then the rules and restrictions can be explained in an easy and intuitive way. Better is that the language is not tied to a particular formalism (a reason why a axiomatic, as opposed to model theoretic, formalism may be prefered)
4. - is syntactically as well as semantically easy to learn/use
5. - does not require the understanding of DL restrictions to use (i.e. is a subset of OWL Full) - although if there is a way that many of these can naturally be covered by DL-based OWL reasoners that is a plus
6. - allows efficient and scalable implementation. Scalability is certainly one key requirement to push this fragment to an enterprise (or web) level.

Proposal

The following subset of language terms, similar to those included in Oracle's OWL Prime, is the suggested starting place. Specifically we could extend RDFS with:

• '"Annotation" Properties:'
  • rdfs:label
  • rdfs:comment
  • rdfs:seeAlso
  • rdfs:isDefinedBy
• (In)Equality:
  • equivalentClass
  • equivalentProperty
  • sameAs
  • differentFrom (and allDifferent)
• Property Characteristics:
  • inverseOf
  • TransitiveProperty
  • SymmetricProperty
  • FunctionalProperty
  • InverseFunctionalProperty
  • ObjectProperty
  • DatatypeProperty
  • disjointWith

Some people have suggested we include class relationships - intersection, union and complement - but only for named classes. I leave this as a matter of discussion.