- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Fri, 13 Feb 2009 23:52:02 -0500 (EST)
- To: public-owl-wg@w3.org
[Response for LC Comment 31] Dear Frank (and many others), Thank you for your message http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0038.html on the OWL 2 Web Ontology Language last call drafts, which the WG has taken to concern adding a syntactic marker for the expressive power of used in an ontology, including which profile the ontology belongs within. One problem with having an expressive power marker in the header of an OWL ontology is that there are syntaxes for OWL ontologies, in particular the preferred syntax, RDF/XML, where the header information is mixed in with the rest of the ontology. Recovering the ontology header in such syntaxes can thus require parsing the entire ontology. Note that simple text processing is not adequate as the marker syntax could occur in places where should not be interpreted as the marker, e.g., in comments or not attached to the ontology node. Another problem is how to treat cases where the expressive power of the ontology does not match the marker. This is very different from what to do if an ontology does adequately reflect reality. Should tools be required to reject ontologies where the expressive power of the ontology is greater than what the marker states? Should tools be required to reject ontologies where the expressive power of the ontology is less than what the marker states? Should nothing be said? What guarantees should a search for expressive markers provide? The answers to these questions are not obvious. The current situation leaves open the possibility that users will get together and, through practice, provide the answers to these thorny questions. Ontology annotations can be used to support this effort. If a body of practice arises, then it may be appropriate for a subsequent working group to consider adding this practice to OWL. Therefore the OWL WG does not intend to make any changes in response to your comment. The discussion of WG issue 111 (see http://www.w3.org/2007/OWL/tracker/issues/111) is not directly related to expressive power markers for OWL ontologies. Instead it more touches on the situation where an ontology only uses the expressive power of OWL 2 DL, but is supposed to be interpreted as an OWL 2 Full document, i.e., that it could not have a finite interpretation. The WG noticed that in such cases it is always possible to add an OWL-2-Full-semantically-vacuous triple to the ontology that is not acceptable in OWL 2 DL, and decided that this would be the preferred way to disambiguate. Some of the discussion of issue 111 did touch on markers for expressive power but the issue itself did not require a solution to this problem. Please acknowledge receipt of this email to <mailto:public-owl-comments@w3.org> (replying to this email should suffice). In your acknowledgment please let us know whether or not you are satisfied with the working group's response to your comment. Regards, Peter F. Patel-Schneider on behalf of the W3C OWL Working Group
Received on Saturday, 14 February 2009 05:20:32 UTC