W3C home > Mailing lists > Public > public-rdf-dawg@w3.org > April to June 2009

Re: "OWL" Entailment

From: Steve Harris <steve.harris@garlik.com>
Date: Fri, 8 May 2009 11:13:14 +0100
Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
Message-Id: <B5F973BA-96DE-443F-B011-A745C6F7F5FB@garlik.com>
To: Bijan Parsia <bparsia@cs.man.ac.uk>
On 6 May 2009, at 18:14, Bijan Parsia wrote:
> 4) Controlling variable range (related to 1)
>
> In OWL systems (such as Pellet, RacerPro, and KAON2) there are two  
> kinds of variables "distinguished" and "non-distinguished" which are  
> distinguishable by what sorts of bindings they allow: names only  
> (and maybe "static" bnodes) or arbitrary elements of the domain.  
> (See around slide 24 of <http://www.cs.man.ac.uk/~bparsia/2006/row-tutorial/index.html 
> >.) It's good to allow for both sorts since distinguished variables  
> are much cheaper to compute but non-distinguished variables get you  
> more answers.

Waaay out of my depth here, but would something like:

   FILTER(isIRI(?distinguished))  or  FILTER(!isBlank(?distinguished))

be sufficient to capture this? I'm not quite sure where/how OWL names  
behave differently to URIs. FWIW, we use some similar optimisations to  
cut the search space in our SPARQL engine, and it's quite easy to  
spot, as long as the user doesn't go out of their way to hide it.

- Steve

-- 
Steve Harris
Garlik Limited, 2 Sheen Road, Richmond, TW9 1AE, UK
+44(0)20 8973 2465  http://www.garlik.com/
Registered in England and Wales 535 7233 VAT # 849 0517 11
Registered office: Thames House, Portsmouth Road, Esher, Surrey, KT10  
9AD
Received on Friday, 8 May 2009 10:13:48 GMT

This archive was generated by hypermail 2.3.1 : Tuesday, 26 March 2013 16:15:38 GMT