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Re: Intersection of properties?

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Sun, 3 Aug 2008 21:50:11 +0100
Message-Id: <D59E6E64-839D-43BF-9B32-C6A38A49DFB7@cs.man.ac.uk>
Cc: "Jeff Thompson" <jeff@thefirst.org>, "Michael Schneider" <schneid@fzi.de>, <public-owl-dev@w3.org>
To: "Gibson, A.P." <A.P.Gibson@uva.nl>

On Aug 3, 2008, at 9:29 PM, Gibson, A.P. wrote:
> > What? The argument against boolean role boxes, in general, is that
> > it's relatively hard to do and there's been relatively little demand
> > for it. ALBO is *very* expressive but, you know, doesn't have
> > cardinality restrictions.
>
> > I personally don't feel a burning desire for role conjunction.
> > Perhaps you could list use cases?
>
> I think that it is hard to gauge demand for currently unsupported  
> expressivity in OWL, as there is no "big list" of expressivity  
> features of different languages from which non-logicians could say  
> "hey that would be really useful in OWL".
>
Rules, Description Graphs, temporal and spatial features, linear and  
arbitrary polynomials....

Ok, it's not a huge list, but someone explicitly requesting property  
intersection presumably has a concrete need.

[snip]
> There seems
>
There is no such seeming.
> to be an underlying expecation in the working group that OWL users  
> will know what expressivity to ask for, and not only that, but they  
> should provide "real" motivating examples to persuade the working  
> group that its worth the effort.
>
The OWL WG is a standardization effort. It, properly, should be  
rather conservative.

However, the OWL ED ethos is that implementors and users (and  
theorists) form a bargain so no one group gets shafted.
> This too is a lot of effort on the users part, especially if the  
> end result is just being told that it is not possible for one  
> reason or another.
>
I assure you that it is a tremendous amount of work on the  
implementor and spec folks too. It's rather frustrating to produce  
something that doesn't get used *and* doesn't get a publication.
> Going out on a limb here - and I dont expect this will happen - but  
> I dont see why OWL-Full can't be furnished with the appropriate  
> syntax for *potential* expressivity like role conjunction so that  
> people will a) know what extentions are theoretically possible and  
> therefore be able to ask for them and b) be able to play around  
> with them (albeit only syntactiacally) and generate the kinds of  
> use cases that you and the working group are looking for, possibly  
> even with tool support for the process.
>

This just isn't a good idea. Especially at the standards level, it's  
quite mad to throw in more stuff on spec without an intention of  
impelmenting it. If you want to play with extensions, try one of the  
first order logic reasoners. Most everything we add is just more  
first order, so it's pretty easy, for some strange value of "easy",  
to experiment qua user.

Cheers,
Bijan.
Received on Sunday, 3 August 2008 21:08:17 GMT

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