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Re: update to the compliance document

From: Jim Hendler <hendler@cs.umd.edu>
Date: Thu, 30 May 2002 13:43:54 -0400
Message-Id: <p05111722b91c12f7202e@[]>
To: Jeff Heflin <heflin@cse.lehigh.edu>, Deborah McGuinness <dlm@ksl.stanford.edu>
Cc: Webont <www-webont-wg@w3.org>

At 11:33 AM -0400 5/30/02, Jeff Heflin wrote:
>It seems to me that by adding universal local range restrictions,
>existential local range restrictions, and local cardinality
>restrictions, that we are almost back at the full language again. As far
>as I can tell, the only thing left out is boolean combination of class
>expressions. If this is the case, then we have to consider whether there
>is really a point in having a compliance level 1.
>As a possible way forward, we should consider the motivation of trying
>to provide a language that tool suite developers can support more
>easily. Of course the problem here is that there are different
>implementor communities that have different ideas of what is "easy to
>support." I see potential implementor communities based around the
>following types of systems:
>1) databases
>2) description logic systems
>3) logic programming (e.g., Prolog)
>4) theorem proving
>Perhaps the thing to do is to figure out what features can be easily
>supported by each of these kind of systems and take the intersection.
>Since the language is evolving out of description logics, then we can
>probably assume everything in full-OWL is easy to do in description
>logic systems, and since FOL theorem provers are even more expressive,
>then we can probably assume that everything is easy in these systems as
>well. That leaves us with databases and logic programming. However, the
>database vendors capabilities may be too restrictive. Their systems
>probably most closely align with plain old RDF + datatypes. Thus, this
>leaves us with the logic programming community. I believe a large number
>of DAML team members are using some variation of logic programming, such
>as traiditional Prolog systems or the XSB system. We could ask them what
>parts of DAML+OIL they implement and then use this as our basis for a
>level 1 language. If we don't, then they are likely to create versions
>of the language that don't meet the compliance level, defeating the
>whole point of compliance levels.

Jeff - two points

  1) As I said in my report from WWW, it appears there is a large and 
growing group of users of DAML who are using what might be called 
"thesaurus" systems -- they publish a vocabulary, but the vocabulary 
was created in a different (usualyy proprietary) system.  These users 
use something similar to what was in SHOE or RDFS, but they also need 
to express some property restrictions - in particular, it is RDFS + 
unambiguous/unique + sometimes real cardinality.  I would venture 
that this is far and away the largest group of current users, and a 
group who OWL Core should support.  These are not group 2 
(description logic) users, and these are people publishing a lot of 
DAML (example, US National Cancer Institute will publish a 40,000 
term thesaurus updated monthly in D+O subset of this kind) - any 
attempts we make to guess what people will do should certainly 
include this group.

   2) I'm not sure what you mean by "almost back at full language" so 
I decided to do the experiment we ran at the f2f -- I took all the 
D+O language features and mapped them against Deb's level 1, and then 
look at the remaining.  I believe the following are NOT in level 1:


(which is a significant group).

I also suspect that not all of these would go in core - or might be 
otherwise simplified, depending on how our issue re: datatypes 
finally works out:

Datatype value

In addition, we haven't discussed whether the "extralogical" things 
we want would also go in core.  I expect they would, so I do not 

I believe the big difference between Core as expressed by Deb and 
Core as proposed at f2f if that at the f2f, we assumed that those 8 
things not currently in core would be in core for "named" classes. 
Deb's document takes them out of core completely.  That seems to me 
to be a very big difference.


Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  240-731-3822 (Cell)
Received on Thursday, 30 May 2002 13:44:34 UTC

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