W3C home > Mailing lists > Public > public-rif-wg@w3.org > November 2007

Re: accuracy check on OWL-DL reasoners

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Wed, 7 Nov 2007 21:51:45 +0000
Message-Id: <4D49C564-1106-4A7D-9975-93FA8DC88D8F@cs.man.ac.uk>
Cc: Chris Welty <cawelty@gmail.com>, "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
To: kifer@cs.sunysb.edu (Michael Kifer)

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 My info was outdated.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  

Received on Wednesday, 7 November 2007 23:02:11 UTC

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