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Re: Relation between OWL and OWL-S

From: Drew McDermott <drew.mcdermott@yale.edu>
Date: Sun, 28 Nov 2004 18:28:32 -0500
Message-Id: <200411282328.iASNSWhi021126@pantheon-po05.its.yale.edu>
To: public-sws-ig@w3.org


> > [me]
> > I think you are still confused about where natural language ends and
> > internal representation begins.
> 
> [Bijan Parsia]
> "Formal" representations? There's not a real sense in which an OWL 
> document is *internal* to anything, in most respects.

One perenially needs a term for "declarative notation used by a
computer that may use mnemonics derived from natural language but is
not actually natural."  I use the term "internal representation."  I
guess one could say "formal" instead, but it's a stretch in the case
of some representations to believe they're formal in any substantive
sense. 

> >   Internally all we have to do is use
> > two different symbols, and the two entities are "differentiated."

> In OWL, this is necessary but not sufficient. 

By "differentiated" I meant "not provably equal," not "provably not
equal." 

> You need to assert or 
> imply a differentFrom in order for them to be required to be distinct 
> (although they will not be required to be the same absent an asserted 
> or implied sameAs; in most cases, differentiation of distinctly named 
> individuals is contingent).
> 
> > (The two names can be made different just by having one be
> > fluvial:bank and the other be mercantile:bank.)  We can give them
> > different properties, but a KR system can believe two entities are
> > different even if it doesn't know any properties that differentiate
> > them.
> 
> Yep, at least in many, as we have explicit inequality. What we don't 
> have is the Unique Name Assumption.

> > Or we can avail ourselves of a really simple difference;
> > for instance, we can declare that economic_entity is disjoint from
> > geographic_entity, so all pairs of objects drawn from economic_entity
> > x geographic_entity are given distinguishing features, because one has
> > the feature "is an economic_entity" and the other has the incompatible
> > feature "is a geographic_entity".
> [snip]
> 
> or just assert that the two individuals are distinct.

If someone wants to split hairs (and there are lots of people hanging
around with nothing better to do, I've noticed --- present company
excepted), they might observe that asserting not(a=b) _is_ a property
that differentiates a and b, to wit, the property of being b, which b
has and a apparently does not.

                                             -- Drew
Received on Sunday, 28 November 2004 23:28:34 GMT

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