- From: Steve Harris <steve.harris@garlik.com>
- Date: Fri, 8 May 2009 11:13:14 +0100
- To: Bijan Parsia <bparsia@cs.man.ac.uk>
- Cc: SPARQL Working Group <public-rdf-dawg@w3.org>
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 UTC