[OWL] On annotating axioms

[Peter F. Patel-Schneider]

From: Denny Vrandecic <dvr at aifb.uni-karlsruhe.de>
Subject: [OWL] On annotating axioms
Date: Wed, 23 Nov 2005 23:36:32 +0100

[...]

> Does this solution fulfill the given conditions?
> 1. The Semantic Web stack is safe and whole. RDF Semantics is adhered 
> to, and OWL semantics is fine, and all syntax regulations imposed by XML 
> and RDF/XML are regarded. Everything is fine.

You have not convinced me of this.  The reification triples and the annotation
triples have semantic import.  What changes will they make to entailment in
OWL?

> 2. Yep, we can annotate single axioms. Axioms have URIs. We can annotate 
> our metadata! Yeah!

> 3. Is it easy to implement? I think it is: for reading OWL ontologies, a 
> tool may just ignore all those extra triples (it can easily filter them 
> out), and still remain faithful to the standard semantics. 

No it can't.  Those triples have semantic import in the standard semantics, and
ignoring them is not allowable.  

> Tools that 
> allow to name axioms (or annotate them) and want to deal with those, 
> have to simply check for the correct reification (RDF toolkits should 
> provide these anyway), and get the axiom's URI.

[...]

> No one holds us back from changing the Abstract Syntax 
> and the OWL XML Presentation Syntax appropriately in order to name 
> axioms far more easy than in the proposed RDF/XML-Syntax. Serializations 
> in RDF/XML-Syntax may get yucky, and the RDF graph of an OWL ontology 
> could become cluttered, but then, so what? 

Well, the problem is that this extra "clutter" has semantic import.
If this extra "clutter" did not have semantic import then there would be very
little wrong with your solution. (Except that why then bother with triples in
the first place?)

> And one can remove all those extra triples (and then the 
> annotations) automatically if wished, without changing the Semantics of 
> the ontology.

Unfortunately, again, no.

[...]

> I hope you won't kill me too hard for this solution :) And I need to 
> change my FOAF-file now, in order to protect my friends...

> best,
> denny