[OEP] Re: Asymmetry of Domain and Range in OWL

Chris:
>The OO people you have been hearing may not go back this far, but slot is 
>indeed an OO term, it was the term used in smalltalk and in CLOS.  If you 
>search around enough, you'll find it still used.  In fact, each new 
>language seems to have decided to invent a new term. I have heard the 
>following terms all used to mean variations on this:
>
>attribute, property, field, slot, member [variable], association, 
>relation, feature, ...
>
>I submit that none of these will quite satisfy all the OO community, but 
>we should pick something and try to use it consistently.  I suspect it 
>would be better to stick with property, since that is what we use.

This brings up a point that I would like to discuss.  We don't need to
satisfy the OO community.  We need to reach the community (or communities) 
that are likely to exploit the Semantic Web once they understand it
sufficiently.  In recent days we have been talking about a number of
issues that all come from an OO background and thus we have been lumping
them together as OO.  I think that these really come from two subcommunities 
of OO: UML users and JAVA users.  We should address their needs and if
possible use terminology familiar to them.


>Finally, and importantly, OO subclass is NOT subsumption, which was 
>precisely my point.  It is almost subsumption, but there is this subtle 
>difference. This is what the note needs to make clear.  There is no way, 
>in first-order logic, OWL, or RDF to characterize the notion of "the class 
>used when an object was created".  This is not closed vs. open world, nor 
>monotonicity, it is unique to the OO paradigm and can't be represented or 
>simulated using the semantics of FOL, OWL, or RDF, because that 
>information (what class was used when an object was created) is not 
>treated differently from any other class an object is an instance of.

I clearly missed your point, in part because I don't think that it is
an important one.  That is, I do not think that the fact that OO languages
have this extra notion of direct instance is a stumbling point for folks
making the transition from OO to OWL.  Instances of a subtype are still 
instances of that class's supertype.  The direct instance distinction
just isn't important here.

What is important for us to address are those things that are "weird" or 
conspicuously missing for these people when using OWL.   The openness
of OWL is weird to someone from an object modeling background for instance.
Some construct for containment is something conspicuously missing for 
others.  We are on the right track with our list of notes which have 
been largely suggested by users who are encountering these problems.  
I think we should stay focused on these and think about how to group
them together where appropriate.

-Evan

Received on Friday, 22 October 2004 23:21:47 UTC