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Re: [OEP] "Classes as values" first draft

From: Natasha Noy <noy@SMI.Stanford.EDU>
Date: Fri, 23 Apr 2004 17:59:56 -0700
Message-Id: <B3E6F1D8-958A-11D8-8395-000A958B5C28@smi.stanford.edu>
Cc: public-swbp-wg@w3.org
To: Alan Rector <rector@cs.man.ac.uk>

Alan,

Your point is well taken. However -- and this certainly my fault -- I 
don't think I was sufficiently clear in the note on what I was trying 
to represent. I really was talking about the subject of an image as in 
the subject of a book. This case is exactly where having classes as 
property values is a more intuitive alternative. I agree with you that 
with your interpretation of subject as being an object on the picture, 
representation issues are different. And your solution, or Aldo's 
prototype solution, are good DL alternatives that achieve the purpose. 
But it's representing a different notion.

I'll change the example to book subject in the second version to avoid 
the confusion.

By the way, for the notion of specific Lion or Shakespeare being the 
subject of a picture, your DL solution does indeed provide the desired 
reasoning properties but incurs maintenance penalties, as some of the 
other solutions in the note: the type hierarchy for restrictions in 
your example essentially parallels the animal hierarchy.

> I think we need two clear guidelines
>
>     One for those who want to stay with OWL-DL,
>     The other for those who want to use OWL-Full
>
> With luck, if we can stick to only one guideline each for OWL-Full and 
> OWL-DL, then we can suggest standard transforms to get from one to the 
> other with a minimum, well defined, distortion of meaning.

That would be ideal, but I doubt we'll be able to achieve that. Even 
with the alternatives that I listed, there were a number of private and 
public responses from people with plenty of practical experience in 
ontology design that said (I am paraphrasing)
- "options 3 and 4 are so bad that they are not worth considering"
- "I  personally would choose 4 if I had to stay within DL"
- "we are using 2a in our case because it was the most practical"

For the moment, let's document what we have and then see of we can 
reach some consensus.

I'll add additional cases, if necessary, to the "classes as values" 
draft, but again, the case the note is considering is the notion of the 
subject in the sense of a subject of a book, rather than specific lion 
in the image. Perhaps we can do the other one separately if needed, 
since the solutions are different.

Natasha
Received on Friday, 23 April 2004 21:00:07 UTC

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