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Re: comment on the fragment document: (inverse) functional and DL-Lite

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Thu, 6 Mar 2008 14:23:11 -0500
Cc: "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
Message-Id: <36A32623-13D2-48A1-BE8F-66B924385E92@cs.rpi.edu>
To: Bijan Parsia <bparsia@cs.man.ac.uk>

I thought the primary idea of DL-Lite was that it would provide  
primary database functionality -- how can it do that without keys?


On Mar 6, 2008, at 6:18 AM, Bijan Parsia wrote:

>
> On 6 Mar 2008, at 11:04, Ivan Herman wrote:
>
>> Boris, Bernardo,
>>
>> I went through
>>
>> http://www.w3.org/2007/OWL/wiki/Fragments_Proposal
>>
>> again today. One thing that I may have missed: I tried to see if I  
>> can use (inverse)functional properties for DL-Lite or not. I did  
>> not find any reference to those neither in 3.1 nor in 3.2. Again, I  
>> may have missed something...
>
> Let's see if I can discern from the text the situation. (As a test  
> of the spec.)
>
> In section 3:
> 	http://www.w3.org/2007/OWL/wiki/Fragments_Proposal#DL-Lite
>
> 	"""Several variants of DL-Lite have been described in the  
> literature. The variant presented here is called DL-LiteR since it  
> allows for property inclusion axioms; it therefore contains the  
> intersection between RDFS and OWL 1.1 DL. Other variants trade  
> property inclusion axioms for functionality and inverse- 
> functionality of object properties."""
>
> I think this is clear that functionality and inverse functionality  
> of *object* properties are forbidden.
>
> Actually ,the rest of the sections are quiet about data properties  
> altogether. Which would mean that data properties are forbidden in  
> this variant. Which means that it's not really the intersection of  
> RDFS and OWL 1.1 DL?
>
> I do think that if we make this DL Lite not have data properties,  
> the text should call that out (e.g., in the list of missing  
> features). OTOH, I think we should allow data properties ;) I would  
> think it would be ok to trade datasubproperties for keys (from a  
> user pov)...I don't know if that would be ok from the logic/ 
> impelmentation pov off the top of my had (while retaining object  
> subproperties).
>
> Cheers,
> Bijan.
>
>
>

"If we knew what we were doing, it wouldn't be called research, would  
it?." - Albert Einstein

Prof James Hendler				http://www.cs.rpi.edu/~hendler
Tetherless World Constellation Chair
Computer Science Dept
Rensselaer Polytechnic Institute, Troy NY 12180
Received on Thursday, 6 March 2008 19:23:24 GMT

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