W3C home > Mailing lists > Public > public-owl-wg@w3.org > March 2008

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

From: Sandro Hawke <sandro@w3.org>
Date: Thu, 06 Mar 2008 20:51:59 -0500
To: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Cc: Jim Hendler <hendler@cs.rpi.edu>, Bijan Parsia <bparsia@cs.man.ac.uk>, "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
Message-ID: <26819.1204854719@ubuhebe>


> Actually, the primary idea of DL-Lite is that it has logspace data  
> complexity, which means that query answering can be implemented using  
> standard (relational) DB technology. In particular, a conjunctive  
> query against a DL-Lite ontology can be re-written as an SQL query  
> against a relational DB containing instance data.
>
> Ian

In what document can/should we say something like that?  I think it's
very important.  (I realize the first part is in Fragments_Proposal, but
not the practical/market angle of its relationship to SQL.)

     - Sandro


> 
> 
> On 6 Mar 2008, at 19:23, Jim Hendler wrote:
> 
> >
> > 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 Friday, 7 March 2008 01:53:17 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Friday, 7 March 2008 01:53:18 GMT