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RE: Axiom annotations

From: Boris Motik <bmotik@cs.man.ac.uk>
Date: Wed, 18 Apr 2007 10:20:29 +0100
To: "'Jeremy Carroll'" <jjc@hpl.hp.com>
Cc: "'Alan Ruttenberg'" <alanruttenberg@gmail.com>, <public-owl-dev@w3.org>, "'chris mungall'" <cjm@fruitfly.org>
Message-ID: <000901c7819a$ced60e30$27c35882@wolf>

Hello,

I completely that it isn't pretty; however, the problem is that RDF does not
allow you to express ternary relations. In the case of the axiom

SubClassOf(Annotation(ap "bla") c1 c2)

you actually have a ternary relationship: the participants are the
annotation, c1, and c2. Since axioms can have more than one annotation, you
actually need a way to represent relationships of arbitrary arity. The only
way that I know of for encoding this into RDF is to reify the relationship.

Sincerely yours,

	Boris

> -----Original Message-----
> From: Jeremy Carroll [mailto:jjc@hpl.hp.com]
> Sent: 18 April 2007 10:17
> To: Boris Motik
> Cc: 'Alan Ruttenberg'; public-owl-dev@w3.org; 'chris mungall'
> Subject: Re: Axiom annotations
> 
> 
> Reification isn't pretty.
> This seems to be only about making something work in practice.
> 
> Jeremy
> 
> 
> 
> Boris Motik wrote:
> > Hello,
> >
> > You are right - we overlooked this point. Would you mind logging this as
> an
> > issue at Google Code?
> >
> > The problem seems to be caused by the fact that, dating from OWL 1.0,
> you
> > could state only binary equivalences, disjointness axioms, etc. in OWL
> RDF.
> > OWL 1.1 inherits this limitation from OWL 1.0 (in order to be backwards
> > compatible); however, as you notice, this has consequences regarding
> > annotations.
> >
> > There are two fixes that I see:
> >
> > 1. One should provide an RDF encoding that does not break up
> equivalences;
> > then, we might tack on the annotations appropriately.
> >
> > 2. A hack would be to simply repeat the axiom annotation on each
> generated
> > equivalence. I am not particularly fond of this, but it is a
> possibility.
> >
> > Thanks for pointing this out!
> >
> > Sincerely yours,
> >
> > 	Boris
> >
> >> -----Original Message-----
> >> From: public-owl-dev-request@w3.org [mailto:public-owl-dev-
> request@w3.org]
> >> On Behalf Of Alan Ruttenberg
> >> Sent: 18 April 2007 01:54
> >> To: public-owl-dev@w3.org
> >> Cc: chris mungall
> >> Subject: Axiom annotations
> >>
> >>
> >>  From http://webont.org/owl/1.1/rdf_mapping.html
> >>
> >>> 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:
> >>>
> >>> _:x rdf:type owl11:Axiom
> >>> _:x T(apIDi) T(cti)   1 ? i ? n
> >>> _:x rdf:subject s
> >>> _:x rdf:predicate p
> >>> _:x rdf:object o
> >> What happens when an Axiom serializes as multiple triples:
> >>
> >>> EquivalentClasses(c1 ... cn) =>
> >>> T(ci) owl:equivalentClass T(ci+1)   1 ? i ? n-1
> >> -Alan
> >
> >
> 
> --
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Received on Wednesday, 18 April 2007 09:21:13 GMT

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