- From: Chris Welty <cawelty@gmail.com>
- Date: Thu, 08 Nov 2007 08:01:45 -0500
- To: Michael Kifer <kifer@cs.sunysb.edu>
- CC: Bijan Parsia <bparsia@cs.man.ac.uk>, "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Michael Kifer wrote: > My argument was that this should not stop us from including > things that are a bit challenging and I gave OWL as an example. Agreed. -Chris > > > --michael > > >> On Nov 7, 2007, at 9:34 PM, Michael Kifer wrote: >> >>> It may be now, but it was not so a year ago. My info was outdated. >>> I see >>> that Racer has announced an upcoming complete version, and Pellet has >>> become complete some 6 months ago. >> This is not true. Pellet was complete almost in 1.3 beta, so sept >> 2005. FaCT++ became complete for OWL DL some months after that. Racer >> has had other design priorities. >> >> Pellet and Racer over a year ago (before OWLED 2006 in Nov 2006) both >> became complete SROIQ reasoners (i.e., OWL 1.1). >> >>> But my point is still valid. >> Well, sorta. I wish it was made with accurate facts :) >> >>> It took >>> quite a few years >> OWL went rec in Feb 2004. So, let's see, 10 months to 2005, and 9 >> months to sept, so 19 months, which is 1 year and 7 months. >> >> This is "quite a few" years? :) >> >> Also, there were SHOQ and SHOQ reasoners before (FaCT, DLP). >> >> Oh, MSPASS was complete and a decision procedure long before, I'm >> prettysure. And Hoolet was complete, but I've not tracked down >> exactly when. I wouldn't call these serious production >> implementations though. >> >>> to achieve a complete implementation after the official >>> release of OWL. Another important point is that without the OWL >>> specification there would probably be little incentive to go all >>> the way >>> and implement those less critical aspects of OWL. >> Hard to say. The main block was the lack of a goal directed decision >> procedure for SHOIQ, which really was quite radically different that >> the EXPTIME logics, due to the loss of the tree like model property. >> Uli and Ian worked on it for 5 years or so. We implemented it shortly >> after they came up with one. >> >> However, we knew how to implement qualified cardinality restrictions, >> and even had user requests, but didn't until we had OWL 1.1 specs we >> were trying to validate. So, I do agree that it can help a lot. If >> you have known procedures, it's even a bit of a no-brainer. >> >> No need to exaggerate to make your point. >> >>> So, if we set the bar too low for RIF then there will be no >>> incentive to >>> work on complete implementations of important features (like equality) >>> either. >> On the other hand, people haven't really taken up the guantlet of a >> complete OWL Full reasoner. So some "reasonableness" judgement is >> required. >> >> Cheers, >> Bijan. >> >> > > > -- Dr. Christopher A. Welty IBM Watson Research Center +1.914.784.7055 19 Skyline Dr. cawelty@gmail.com Hawthorne, NY 10532 http://www.research.ibm.com/people/w/welty
Received on Thursday, 8 November 2007 13:02:00 UTC