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test case A and superProperty

From: Brian McBride <bwm@hplb.hpl.hp.com>
Date: Mon, 01 Jul 2002 18:55:28 +0100
Message-Id: <>
To: RDF Core <w3c-rdfcore-wg@w3.org>, Pat Hayes <phayes@ai.uwf.edu>

As per my recent posts (sorry for the shotgun effect, I wanted to keep the 
threads separate), its been suggested that we can have test case A be yes 
and test case C be no.

I just wanted to note that there is an interaction between this test case 
and rdfs:subPropertyOf.  Consider:

   _:a dc:title "4th July" .
   _:b dc:date  "4th July" .

[I don't know DC well enough to know whether this is a realistic example, I 
suspect not so consider this just illustrative]

All is reasonably well.  With appropriate datatype range constraints one of 
these denotes a string and the other a date.

Now add a common super property for all the dc properties:

   dc:property rdf:type        rdf:Property .
   dc:title rdfs:subPropertyOf dc:property .
   dc:date  rdfs:subPropertyOf dc:property .

This now entails:

   _:a dc:property _:l .
   _:b dc:property _:l .

I assume this is still monotonic, since I haven't actually retracted 
anything, though it sure feels like changing my mind to me.

A more extreme form is to postulate the existence of a common super 
property of all properties, which we have talked about in the past.  If 
there were such a thing and the answer to A is yes, then we'd have tidy 
literals anyway.

At this point I think I need to hear Pat say, "relax".

Received on Monday, 1 July 2002 13:56:20 UTC

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