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Re: Can a property not have a uriref?

From: Zhang Jeff <jeffzhang726@yahoo.com.cn>
Date: Tue, 17 Sep 2002 18:08:38 +0800 (CST)
Message-ID: <20020917100838.90953.qmail@web20706.mail.yahoo.com>
To: www-rdf-interest@w3.org

 --- Murray Spork <m.spork@qut.edu.au> 的正文:> 
> 
> Hi all,
> 
> I had assumed that all predicates must be named by
> some uriref - this 
> seems obvious where a predicate appears in a simple
> s o p triple.
> 
> Then I thought of an example where you declare a
> resource of type 
> "rdf:Property" without giving it a uriref - but even
> if this is valid 
> RDF (would it be?) it wouldn't make sense cause you
> could never use it 
> in a triple.
> 
> But today I thought of another possible counter
> example (where we are 
> dealing with reification) that may actually make
> sense in some 
> circumstances.
> 
> Can a property node that is part of a reification
> statement be an 
> anonymous node? Below is a modification of the
> example given in the Primer:
> 
> <rdf:RDF
>   
>
xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
>    xmlns:a="http://description.org/schema/">
>    <rdf:Description>
>      <rdf:subject
> resource="http://www.w3.org/Home/Lassila" />
>      <rdf:predicate>
>      	<rdf:Description>
> 	    <rdf:type	 
>
resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property"
> />
>      	<rdf:Description>
>      <rdf:predicate>
>      <rdf:object>Ora Lassila</rdf:object>
>      <rdf:type 
>
resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Statement"
> />
>      <a:attributedTo>Ralph Swick</a:attributedTo>
>    </rdf:Description>
> </rdf:RDF>
> 
> 

I don't think it's a legal reification.
Property is some uri reference standing for some
specific meaning and is used to describe something
(which is called resource in rdf context).
I don't know what sense could a not-specified 
property make.
One may really want to describe that" A has some
unknow property PX with value B" but the statement 
is an statment in sense of natural language,but not 
an RDF statement.So there is no reificaiton could be 
done on it.


> IOW I am asserting that there exists some Statement
> that has a subject 
> "http://www.w3.org/Home/Lassila", an object "Ora
> Lassila" and that has a 
>   predicate which is some (unamed) Resource. Other
> properties could be 
> attached to the Property bnode to further describe
> it without actually 
> naming it.
> 
> Is this allowable/ make sense? If affirmative - then
> a property need not 
> have a uriref?
> 
> BTW - "Property" and "predicate" appear to be used
> interchangeably - are 
> they the same concept?
> 
> -- 
> Murray Spork
> Centre for Information Technology Innovation (CITI)
> The Redcone Project
> Queensland University of Technology, Brisbane,
> Australia
> Phone: +61-7-3864-9488
> Email: m.spork@qut.edu.au
> Web: http://redcone.gbst.com/
>  

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Received on Tuesday, 17 September 2002 06:08:40 GMT

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