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Re: DAML: About Thing, Nothing and the "universe of discourse"

From: pat hayes <phayes@ai.uwf.edu>
Date: Tue, 19 Dec 2000 10:06:13 -0800
Message-Id: <v04210106b665525de863@[204.214.21.208]>
To: Jim Hendler <jhendler@darpa.mil>
Cc: www-rdf-logic@w3.org
>>PPS: There are other issues to be resolved with respect to fooThing.  For
>>example, would it be disjoint from barThing, where barThing is the top of
>>some other ontology?
>>
>
>Seems to me that defining a default Thing (and possibly a bottom) 
>would make things much easier in general for all of the various 
>parties involved -- by rooting all the ontologies at the same root 
>node, there would be both mathematical advantages (whole inheritance 
>hierarchy would become a rooted graph, and in most cases a rooted 
>DAG)  as well as obvious interoperability advantages.   What would 
>be the advantage of letting each designer do their own (and why 
>wouldn't we want a global one)

The advantage of allowing a designer 'do their own' would be that one 
person's universe might well be a subset of someone else's universe. 
There are DAML ontologies already out there which basically talk 
about universes consisting of very limited domains 
(people+employers+dates+numbers, say; but not including fish, 
recipes, ideas of the infinite or interstellar clusters of ionised 
hydrogen.) Now, one can take the view that 'top' means something like 
'universal top', but by doing so one kind of insists that everyone's 
top is rather a long way, speaking conceptually, from all their 
actual categories. Why not allow one ontology's Top to be lower than 
another's (or even sideways from, allowing a 'larger' ontology to 
refer to both of them and place them in separate divisions in its 
universe)?
Each ontology is still rooted, but they don;t all have the same root. 
One could have an equal-top rule as a default if that is required to 
give global coherence.

>-- I have often stated that IMHO the best "high-level ontology" for 
>the web would be the single node "Thing" (or, perhaps that should be 
>http://...//DAML+OIL:DOThing or RDFS:RDFSThing)
>
>
>Dr. James Hendler		jhendler@darpa.mil
>Chief Scientist, DARPA/ISO	703-696-2238 (phone)
>3701 N. Fairfax Dr.		703-696-2201 (Fax)
>Arlington, VA 22203		http://www.cs.umd.edu/~hendler

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Received on Tuesday, 19 December 2000 13:04:23 GMT

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