UPDATE: initial message concerning syntax

		Providing Syntax for SWOL

The syntax for the Semantic Web Ontology Language (SWOL) may be more
contentious than its semantics.  In particular, there may be several
syntaxes, to support several modes of interaction.

I think that is would be a good idea to get the details of one syntax
ironed down.  I've picked on an XML syntax for SWOL.


The Basic Problem:

SWOL is supposed to be an extension of RDF.  As such, the semantics of SWOL
should be upward compatible with the semantics of RDF.  That is, that SWOL
entailment reduces to RDF entailment on RDF knowledge bases.  However, if
the syntax of SWOL is just RDF triples, then there will be RDF knowledge
bases where this is not true, namely RDF knowledge bases that contain
triples that encode SWOL syntax.  Therefore, I have developed a draft
syntax that distinguishes between the RDF and non-RDF parts of SWOL.


The Approach:

I have tried to develop a syntax that allows SWOL syntax processing to use
standard XML tools as much as possible.   To that end I have specified SWOL
syntax in terms of the XQuery 1.0 and XPath 2.0 Data Model.  This makes the
syntax harder to develop and harder to read, but should have important
benefits for implementers.   An initial stab at the syntax specification is
given in an attachment.  Examples of the syntax are given in another
attachment.

Note:  The syntax is much less developed than the semantics.  I welcome any
       help in determining better ways of doing this.  In particular the
       syntactic names are taken from DAML+OIL and there are undoubtably
       better ones available.



Action Items for the Clean-Up Task Force:

[Again, relevant comments from other WG members are welcome.]

1/ Review the attachment.

2/ Determine if you disagree with the following:
   - Upward semantic compatibility with RDF is important.
   - The proposed solution allows this upward semantic compatability.
   - The proposed solution does not introduce other problems.

3/ Make suggestions to improve the syntax or fill in holes in the syntax.


Schedule:


morning of 20 December 2001: comments on the approach back to me
7 January 2002: draft document for face-to-face discussion