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RE: Annotations cause RDF axioms to disappear?

From: Booth, David (HP Software - Boston) <dbooth@hp.com>
Date: Mon, 28 Jul 2008 15:29:11 +0000
To: Ian Horrocks <horrocks@cs.man.ac.uk>
CC: "public-owl-comments@w3.org" <public-owl-comments@w3.org>
Message-ID: <184112FE564ADF4F8F9C3FA01AE50009FCFC70850F@G1W0486.americas.hpqcorp.net>

Hi Ian,

My overall concern is to ensure that RDF data from multiple sources can be usefully combined and used by RDF applications that are not OWL2-aware, even if *some* of the data originated as OWL2.  It is great if they can monotonically get *more* value from being OWL2-aware, but they should still get as much value as possible even if they are not OWL2-aware.

Given that the intended semantic interpretation of an OWL2 annotated statement is that the original axiom is still asserted when the annotation is added, it would make sense to me to have the RDF include both the axiom and the reified version with the annotation.   So yes, I believe that proposed solution would satisfactorily address my concern.

Thanks


David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com
http://www.hp.com/go/software

Statements made herein represent the views of the author and do not necessarily represent the official views of HP unless explicitly so stated.


> -----Original Message-----
> From: Ian Horrocks [mailto:horrocks@cs.man.ac.uk]
> Sent: Saturday, July 26, 2008 3:06 PM
> To: Booth, David (HP Software - Boston)
> Cc: public-owl-comments@w3.org
> Subject: Re: Annotations cause RDF axioms to disappear?
>
> David,
>
> Annotation of axioms is an important new feature in OWL 2. When
> mapping annotated axioms to RDF, the annotation needs to be attached
> to a triple. In order to do this, the triple is reified.
>
> There is currently a discussion in the OWL Working Group as to
> whether, for annotated axioms, the mapping should be changed to
> generate *both* the "base triple" (s p o) and the reified (and
> annotated) version. Would this solve your problem? I can't guarantee
> that this will come to pass, because "duplicating" the triple also
> has it's drawbacks, but knowing your position would be useful input
> to the debate.
>
> Regards,
> Ian
>
>
>
> On 22 Jul 2008, at 03:03, Booth, David (HP Software - Boston) wrote:
>
> >
> > Section 3 of OWL 2 Web Ontology Language: Structural Specification
> > and Functional-Style Syntax says:
> > http://www.w3.org/TR/2008/WD-owl2-syntax-20080411/#Ontologies
> > [[
> > 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:
> > http://www.w3.org/TR/2008/WD-owl2-mapping-to-rdf-20080411/
> > #Annotated_Axioms
> > [[
> > 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
> > http://www.hp.com/go/software
> >
> > 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 Monday, 28 July 2008 15:30:05 GMT

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