W3C home > Mailing lists > Public > www-rdf-interest@w3.org > October 2000

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

From: Graham Klyne <GK@dial.pipex.com>
Date: Mon, 02 Oct 2000 14:16:29 +0100
Message-Id: <4.3.2.7.2.20001002141333.00bc18a0@pop.dial.pipex.com>
To: Ian Horrocks <horrocks@cs.man.ac.uk>
Cc: rdf interest <www-rdf-interest@w3.org>
Ian,

I think what you describe has exactly the same effect as Jan Grant's recent 
suggestion:

>and loosely:
>
>P has a range of (a member of the union of A and B)
>
>         A --[rdfs:subclassOf]-> anon:C
>         B --[rdfs:subclassOf]-> anon:C
>         P --[rdfs:range]-> anon:C
>
>(give anon:C a real URI if you prefer).

except that Jan's approach doesn't depend on additional 
application-specific awareness.  Or am I missing something?

#g
--


At 02:17 PM 9/30/00 +0100, Ian Horrocks wrote:
>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

------------
Graham Klyne
(GK@ACM.ORG)
Received on Monday, 2 October 2000 09:40:58 GMT

This archive was generated by hypermail 2.2.0+W3C-0.50 : Monday, 7 December 2009 10:51:44 GMT