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Re: A proposal for ISSUE-104 (built-in vocabulary)

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Wed, 11 Jun 2008 12:34:50 -0400
Message-Id: <98A706AE-463B-4005-BB33-E8F458FCA445@gmail.com>
Cc: <public-owl-wg@w3.org>
To: "Boris Motik" <boris.motik@comlab.ox.ac.uk>

I would leave us uncommitted on the question whether the properties  
are object or data properties, instead leaving this to modelers. If  
both sense were used, the ontology would be OWL Full.

This isn't optimal, but an advance over the current situation in  
which they can't be modeled with at all.


On Jun 11, 2008, at 6:33 AM, Boris Motik wrote:

> Hello,
> The discussion around ISSUE-104 (reserved vocabulary) seemed to  
> show that lists and reification are the main, if not the only part
> of the reserved vocabulary that might be useful in OWL 2 DL. (If we  
> feel that it is necessary, we may verify this by sending an
> e-mail to owl-dev once we have fleshed out our proposal. I  
> personally don't think we need to do this, given my experience how the
> built-in vocabulary has been used in OWL 1.)
> Based on the assumption that we more or less agree on the above  
> observation, I would like to put forward a proposal for resolving
> this issue. Before I do so, let me first explain why the obvious  
> way of resolving the problem does not work.
> 1. A slight problem with exempting rdf:List from the reserved  
> vocabulary
> ---------------------------------------------------------------------- 
> --
> For a property to be used in any OWL 2 DL axiom, the property must  
> be declared as either an object or a data property. Now this
> causes a slight problem for rdf:List: we would make a hard-and-fast  
> choice about how to treat rdf:first. Thus, we would have to
> decide whether rdf:first is an object or a data property, which  
> would essentially restrict the usage of lists in OWL 2 DL in a nasty
> way.
> 2. A possible way forward
> -------------------------
> To allow for lists, we would introduce four new vocabulary elements  
> in OWL 2:
> - owl:List
> - owl:firstLiteral
> - owl:firstIndividual
> - owl:rest
> To ensure semantic compatibility with OWL Full, we would make  
> owl:List a subclass of rdf:List, owl:firstLiteral and
> owl:firstIndividual a subproperty of rdf:first, and owl:rest a  
> subproperty of rdf:rest.
> We would extend the structural spec to provide built-in  
> declarations for these properties (in the obvious way). We would  
> also add a
> subsection to the structural spec and to the primer about how these  
> are to be used in ontologies.
> We would leave the rest of the built-in vocabulary in OWL 2 DL as  
> it currently is.
> Note that this does not address the reification vocabulary.  
> Reification is considered bad in RDF anyway, and it would introduce
> similar problems in OWL 2 DL; therefore, it seems to me that  
> disallowing it in OWL 2 DL is not a big deal.
> Let me know how you feel about this.
> Regards,
> 	Boris
Received on Wednesday, 11 June 2008 16:35:31 UTC

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