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Annotations cause RDF axioms to disappear?

From: Booth, David (HP Software - Boston) <dbooth@hp.com>
Date: Tue, 22 Jul 2008 02:03:54 +0000
To: "public-owl-comments@w3.org" <public-owl-comments@w3.org>
Message-ID: <184112FE564ADF4F8F9C3FA01AE50009FCFC5E87ED@G1W0486.americas.hpqcorp.net>

Section 3 of OWL 2 Web Ontology Language: Structural Specification and Functional-Style Syntax says:
OWL 2 allows each axiom to contain annotations. These can be used to associate arbitrary information with an axiom. This information does not affect the semantics of the language in any way.

But Section 2.1 of OWL 2 Web Ontology Language: Mapping to RDF Graphs says:
Axioms with annotations are reified. If s p o is the RDF serialization of the corresponding axiom without annotations given in Table 2 and the axiom contains annotations Annotation(apIDi cti), 1  i  n, then, instead of being serialized as s p o, the axiom is serialized as follows . . . .

In other words, from a strictly OWL 2 perspective, the reified axioms (apparently) still carry the same semantics as the non-reified axioms.  However, from an RDF perspective there is an enormous difference: an annotation causes the axioms to disappear!  Given that the axioms are usually the main point of OWL/RDF statements -- though of course this is a subjective -- it seems quite unfortunate that they disappear by the mere addition of an annotation.

Have I understood this correctly?  If so, this looks to me like it would be a significant problem in making OWL 2 work well with other RDF, as RDF is combined from multiple sources, some of which might have orginally been OWL 2.

David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com

Statements made herein represent the views of the author and do not necessarily represent the official views of HP unless explicitly so stated.
Received on Tuesday, 22 July 2008 02:05:11 UTC

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