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Re: Axiom annotations

From: Michael Schneider <m_schnei@gmx.de>
Date: Wed, 18 Apr 2007 22:36:39 +0200
Message-ID: <46268157.3000502@gmx.de>
To: public-owl-dev@w3.org

Hi, second time!

Alan Ruttenberg wrote on Tue, 17 Apr 2007:

>  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

If I correctly understand Alan's above citation from the draft, this is 
meant as an "EITHER s p o OR reification" (whatever form of reification 
will be used in the end).

So, if I take my old but beloved OWL1.0 compliant ontology, which is 
serialized in RDF, and then cautiously start to add a few comments to 
all its axioms, I would not recognize the original RDF anymore, because 
all those s p o statements representing the axioms would now have been 
replaced by ugly and fat reifications? So still exactly the same 
ontology (annotation have no semantic implications, right?), but now 
with a largely different serialization. I would not like this!

Really, I would prefer to have a "ALWAYS s p o AND ADDITIONALLY 
reification IF NEEDED FOR ANNOTATION". This would be more conservative, 
even my old OWL1.0 parser would recognize this ontology, because it 
would simply ignore the additional reification.

The drawback would of course be that there would be one more statement 
within the serialization of an annotated axiom. But I could live with 
this easily: Reification adds four statements plus one for the 
annotation, so enlargement would be (at most) 20%. And specifically, 
RDF/XML provides me with a nice syntactic trick to get reification from 
an existing triple, by adding an 'rdf:ID' attribute to the predicate 
property, see

   http://www.w3.org/TR/rdf-primer/#example20

So my XML serialization would be even /smaller/ in comparison with 
reification without the s p o triple included.

Bye,
Michael
Received on Wednesday, 18 April 2007 20:31:48 GMT

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