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From: Franco Salvetti <franco.salvetti@tiscalinet.it>
Date: Wed, 3 Jul 2002 17:07:15 +0200
Message-ID: <006101c222a3$51930b40$14130a3e@hobbit>
To: <www-rdf-comments@w3.org>
Cc: <boley@informatik.uni-kl.de>

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"/>

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? 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?


<rdf:Property rdf:about="http://www.w3.org/2000/01/rdf-schema#isDefinedBy">
  <rdfs:isDefinedBy rdf:resource="http://www.w3.org/2000/01/rdf-schema#"/>
  <rdf:type resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property"/>
  <rdfs:subPropertyOf rdf:resource="http://www.w3.org/2000/01/rdf-schema#seeAlso"/>
  <rdfs:label xml:lang="en">isDefinedBy</rdfs:label>
  <rdfs:comment>Indicates the namespace of a resource</rdfs:comment>
  <rdfs:range rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>
  <rdfs:domain rdf:resource="http://www.w3.org/2000/01/rdf-schema#Resource"/>

it seems to me that there is 2 (two) definition of isDefinedBy in terms of rdf:type.

The first line for me is the same statement than the one in line 3. Am I right?

all the best
Franco Salvetti

p.s. sorry if I bother you but I'am working on it for my thesis and I see that there are many things not well definited
Received on Wednesday, 3 July 2002 10:59:40 UTC

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