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Re: accuracy check on OWL-DL reasoners

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Wed, 07 Nov 2007 18:56:49 -0500
To: Bijan Parsia <bparsia@cs.man.ac.uk>
Cc: Chris Welty <cawelty@gmail.com>, "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
Message-ID: <20076.1194479809@cs.sunysb.edu>

OK, I was wrong about the exact timing for OWL-DL.  OWL-Full is still not
completely implemented.  But that was not my point.

The discussion was about whether to include equality in RIF and at what
level. Just as with OWL-DL, it is well-known how to implement equality, but
I do not know of any rule system that actually did so seriously and in a
complete way.  My argument was that this should not stop us from including
things that are a bit challenging and I gave OWL as an example.


> 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 My info was outdated.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.
Received on Wednesday, 7 November 2007 23:57:04 UTC

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