Layering on RDFS

This is what I sent as my f2f report to HP, I think I treated RDFS
relatively clearly ....

> Semantic Layering
> =================
With the resolution of this issue the likely final outcome will be three
levels in OWL, currently named:

   OWL Lite
   Fast OWL
   Large OWL

(van Harmelen has an action to rename all three levels).

To understand these we first need to divide RDFS into two parts:

   beginners RDFS - which uses RDFS to describe a vocabulary
   advanced RDFS - which uses RDFS to describe or extend its own vocabulary.

   OWL Lite extends beginners RDFS
   Fast OWL extends OWL Lite (but does not allow advanced RDFS)
   Large OWL extends both Fast OWL and advanced RDFS

   OWL Lite and Fast OWL are decidable
   Large OWL is semidecidable

In practice that means that we expect the full functionality of Fast OWL
to be implemented, whereas some aspects of Large OWL will not be, and we
will not define a minimal requirement for Large OWL implementations over
and above Fast OWL. A typical Large OWL implementation will have a
complete RDFS implementation and a complete Fast OWL implementation in a
single module. There will be incompleteness in the cracks between RDFS
and Fast OWL.

This is a good outcome for the Jena team in that we aspire to having
both a complete RDFS and a complete Fast OWL implementations, and being
able to put them together in a single framework (Large OWL) is highly


Received on Friday, 18 October 2002 04:02:37 UTC