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Re: error?

From: pat hayes <phayes@ai.uwf.edu>
Date: Mon, 8 Jul 2002 13:34:31 -0700
Message-Id: <p05111b1ab94fa6a4a728@[192.168.0.146]>
To: "Franco Salvetti" <franco.salvetti@tiscalinet.it>
Cc: www-rdf-comments@w3.org

>Hi,
>
>in the definition of RDFS (official document) there is:
>
><rdf:Property about="http://www.w3.org/1999/02/22-rdf-syntax-ns#object">
>   <rdfs:isDefinedBy 
>rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#"/>
>   <rdfs:label xml:lang="en">object</rdfs:label>
>   <rdfs:comment>The object of an RDF statement.</rdfs:comment>
>   <rdfs:domain 
>rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement"/>
></rdf:Property>
>
>I see that there is not a statement about that rdfs:range of the 
>property rdf:object. In consideration that the range of a property 
>is the union on any single range I think that we can add this two 
>lines at the definition of the property rdf:object
>
>   <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
>   <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Literal"/>
>
>so that an rdf:object can be either an rdfs:Resource or an rdfs:Literal.
>
>A question arise sponteneusly: Can an instance of the class 
>rdfs:Literal be a resource?

Good question. My own take on this is that 'resource' means simply 
'entity', ie anything whatsoever. In which case, the answer is YES, a 
literal can be a resource.

>I hope NO, because the definition of the rdfs:domain of the property 
>rdf:subject is an rdfs:Resource and we know that we cannot have as a 
>subject of an RDF statement a stupid string on characters. Do am I 
>right?

Why cannot a string be the subject of a statement? Strings can have 
properties (such as being written in French, containing no numerical 
characters, being at most 64 characters long, having been composed on 
a certain date) and so they can legitimately be subjects of RDF 
assertions, surely? I would prefer it, in fact, if RDF allowed 
literals to be in the subject position: the restriction which 
prohibits this is an artifact of the arbitrary (and basically 
confused)  rules of XML syntax.

Pat Hayes

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Received on Monday, 8 July 2002 16:34:20 GMT

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