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Re: range, domain: Conjunctive AND disjunctive semantics both supportable

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Sat, 30 Sep 2000 14:17:09 +0100 (BST)
To: rdf interest <www-rdf-interest@w3.org>
Message-ID: <14805.57578.271800.860229@localhost.localdomain>
In the OIL language (see http://www.ontoknowledge.org/oil/) we extend
RDF schema with (amongst other things) logical constructs that allow
you to say things like:

	P --[rdfs:range]-> (A or B)

This approach has many advantages: it allows disjunctive semantics to
be exactly captured and it saves cluttering up the class hierarchy with
unwanted classes. Of course the meaning would only be accessible to
OIL-aware agents.

In this setting, given 

	S --P--> O

we can infer

	O --rdf:type--> (A or B)

Note that this is NOT the same as being able to infer either

	(O --rdf:type--> A)
or 
	(O --rdf:type--> B)

As for validity checking, without being able to express e.g., negation
or disjointness, then "validation" is not very meaningful as we can
never infer invalidity - we can only infer tighter constraints.

Regards, Ian
Received on Saturday, 30 September 2000 10:42:08 GMT

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