- From: Bijan Parsia <bparsia@cs.man.ac.uk>
- Date: Wed, 4 Feb 2009 20:36:22 +0000
- To: public-owl-wg Working Group <public-owl-wg@w3.org>
http://www.w3.org/2007/OWL/wiki/LC_Responses/FH4 The message is also appended below as well. Cheers, Bijan. To: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl> CC: public-owl-comments@w3.org Subject: [LC response] To Frank van Harmelen Dear Frank, Thank you for your comment <http://lists.w3.org/Archives/Public/public-owl-comments/ 2009Jan/0037.html> on the OWL 2 Web Ontology Language last call drafts. First, we'd like to note that this is not a change to the *language* but merely a change in the *presentation* of the language. No new capability, esp. from the RDF perspective, has occurred. In the old specification: <http://www.w3.org/TR/owl-semantics/> the patterns of admissible blank nodes (roughly, tree like patterns that can be mapped to nested someValuesOf) could be specified without recourse to nodeIDs due to the (tree-like) frame structure of Abstract syntax constructions. Unfortunately, this is not possible in the new functional syntax, hence we must make use of a different mechanism to express the same point. Additionally, we believe there is value in having explicit nodeIDs, borrowing from RDF, since it makes it clear that there is an actual, significant syntax item there. Here is an example of the difficulty (following the productions in <http://www.w3.org/TR/owl-semantics/syntax.html#2.2>): """The syntax here is set up to somewhat mirror RDF/XML syntax [RDF Syntax] without the use of rdf:nodeID.""" ABSTRACT SYNTAX: Individual(anObjectProperty Individual(aDataProperty "foo")) TURTLE: [anObjectProperty [aDataProperty "foo"]] TURTLE WITH NODEIDS: _:x anObjectProperty _:y. _:y aDataProperty "foo". FUNCTIONAL SYNTAX: PropertyAssertion(anObjectProperty _:x _:y) PropertyAssertion(aDataProperty _:y "Foo") This is essentially an issue of surface syntax used in the specification. The FS is designed such that axioms in the FS correspond to axioms in first order logic (which makes various specification issues easier). This makes it impossible to use implicit BNodes. Furthermore, given the tradition of using nodeIDs, we feel we are well within best practice. Accordingly, the working group has decided not to make the change you've suggested. 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, Bijan Parsia on behalf of the W3C OWL Working Group
Received on Wednesday, 4 February 2009 20:32:57 UTC