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Re: What about sub property chains for datatype properties? (ISSUE-8)

From: Uli Sattler <sattler@cs.man.ac.uk>
Date: Mon, 5 Nov 2007 15:13:23 +0000
Message-Id: <85304B6D-A40E-415C-9E30-D0B0C0E9A02A@cs.man.ac.uk>
Cc: "Owl Dev" <public-owl-dev@w3.org>
To: Michael Schneider <schneid@fzi.de>

Hi Michael,

there are reasons why these sub-property chains are only made up of  
object properties:  decidability in OWL (DL and 1.1) relies on the  
fact that "datatype consistency" can be checked for each object  
separately, without referring to other objects and the values of  
their datatype properties. If we would need to do this, we would more  
likely be in trouble, and would need to

- be much more careful about what datatypes and datatype predicates  
to allow without loosing decidability and
- use more complex reasoning mechanisms that have, to the best of my  
knowledge, only been described on paper and never been implemented or  

So, I can see your use case, but I don't think we know enough about  
this yet.

If you want to know more, check out

Carsten Lutz and Maja Milicic. A Tableau Algorithm for Description  
Logics with Concrete Domains and General TBoxes. Journal of Automated  
Reasoning. To appear.

Carsten Lutz. Description Logics with Concrete Domains - A Survey. In  
Philippe Balbiani, Nobu-Yuki Suzuki, Frank Wolter, and Michael  
Zakharyaschev, editors, Advances in Modal Logics Volume 4. King's  
College Publications, 2003.

Cheers, Uli

On 2 Oct 2007, at 13:26, Michael Schneider wrote:

> Hi!
> It just stroke me that there seem to be only Sub/Object/ 
> PropertyChains in
> the current OWL-1.1 draft [1]. Does anyone know if there is a  
> problem with
> also having sub property chains of the form
>   SubDataPropertyOf(
>       SubDataPropertyChain(R1 ... Rn-1 Dn)
>       D )
> where Dn and D are DataPropertyS (having compatible datatypes as their
> ranges), while R1 ... Rn-1 are ObjectPropertyS?
> With such a SubDataPropertyChain, one could for instance translate  
> rules
> like:
>   ?x hasFather ?y AND ?y hasFamilyName ?fn
>   ==> ?x hasFamilyName ?fn
> with ?fn being an xsd:string, into an equivalent OWL axiom
>   SubDataPropertyOf(
>       SubDataPropertyChain(hasFather hasFamilyName)
>       hasFamilyName )
> In this case, the super property whould equal the final chain  
> property (both
> 'hasFamilyName').
> An example for a more general rule type (the analogon of the  
> 'uncle' rule)
> would be:
>   ?g containsUser ?u AND ?u hasUserID ?i
>   ==> ?g containsUserWithID ?i
> where ?g would stand for some user group. Here, the DataPropertyS
> 'hasUserID' and 'containsUserWithID' differ from each other,  
> because they
> are intended to have a different meaning.
> Any ideas, if this feature has a chance to enter the family of  
> OWL-1.1 (or
> 1.2 :)) axioms? Or did I overlook some fundamental issue here?
> Cheers,
> Michael
> [1] OWL-1.1 Semantics
>     http://www.webont.org/owl/1.1/semantics.html#2
> --
> Dipl.-Inform. Michael Schneider
> FZI Forschungszentrum Informatik Karlsruhe
> Abtl. Information Process Engineering (IPE)
> Tel  : +49-721-9654-726
> Fax  : +49-721-9654-727
> Email: Michael.Schneider@fzi.de
> Web  : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555
> FZI Forschungszentrum Informatik an der Universität Karlsruhe
> Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe
> Tel.: +49-721-9654-0, Fax: +49-721-9654-959
> Stiftung des bürgerlichen Rechts
> Az: 14-0563.1 Regierungspräsidium Karlsruhe
> Vorstand: Rüdiger Dillmann, Michael Flor, Jivka Ovtcharova, Rudi  
> Studer
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Received on Monday, 5 November 2007 15:20:27 UTC

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