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Re: Anonymous Instances & Use of rdf:Resource as a class

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Thu, 17 Jul 2003 20:03:39 +0300
To: Gary.Ng@networkinference.com
Cc: www-rdf-logic@W3.Org
Message-Id: <200307172003.39479.jjc@hpl.hp.com>


Hi Gary

> 1. How should a parsing tool handle things that are declared to be
> rdf:Resource?

rdfs:Resource

OWL S&AS excludes rdfs:Resource completely from OWL DL, see
http://www.w3.org/TR/owl-semantics/mapping.html#disallowed_rdf_vocabulary

so your

> b. Strictly speaking, this should not be allowed. Since although
> owl:Thing is a rdf:Resource, but not all rdf:Resources are owl:Thing,
> and for a OWL-DL tool, this has gone out of the boundary and I would say
> this falls into OWL-FULL.

is correct

> 2. Anonymous instances vs named instances. What is expected of them? 

> Are all anonymous instances assumed unique?

You are right in understanding "No" here. In OWL DL it follows from the way 
that unnamed individuals are handled in the direct semantics in OWL Full it 
follows from the way that blank nodes are handled in the RDF Semantics ...

I guess if you really wanted I could try and prove it in one or both systems - 
I don't believe either document calls this out as a feature.

In particular note the following example

eg:i rdf:type owl:Thing .
eg:i eg:prop _:a .
eg:i eg:prop _:b .
_:a rdf:type owl:Thing .
_:b rdf:type owl:Thing .
eg:prop rdf:type owl:ObjectProperty .

entails and is entailed by

eg:i rdf:type owl:Thing .
eg:i eg:prop _:a .
_:a rdf:type owl:Thing .
eg:prop rdf:type owl:ObjectProperty .


In the terms of Mugnier and Chein

Michel Chein, Marie-Laure Mugnier. Conceptual Graphs: Fundamental Notions, 
Revue d'Intelligence Artificielle, volume 6-4, pages 365-406, 1992.

http://www.lirmm.fr/~mugnier/ArticlesPostscript/RIA92ChMu.ps

the second graph is an irredundant version of the first.


Jeremy
Received on Thursday, 17 July 2003 14:04:05 GMT

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