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About rdfs:member and rdf:_nnn

From: Qu Yuzhong <yzqu@seu.edu.cn>
Date: Sun, 16 Feb 2003 23:59:25 +0800
Message-ID: <005d01c2d5d4$62288180$260f77ca@proxy.seu.edu.cn>
To: "rdf-comments" <www-rdf-comments@w3.org>
Cc: <bwm@hplb.hpl.hp.com>, <phayes@ai.uwf.edu>, <rguha@us.ibm.com>, "Dan Brickley" <danbri@w3.org>

Comments on rdfs:member and rdf:_nnn.

1. About rdfs:member
 
Why not constraint the rdfs:domain of rdfs:member to be rdfs:Container? 
   (3.3 RDFS interpretations of the RDF Semantics spec)

    Consider adding an axiomatic triple as follows:
    rdfs:member rdfs:domain rdfs:Container

Why not specify rdfs:member to be an instance of rdfs:ContainerMembershipProperty?
   (3.3 RDFS interpretations of the RDF Semantics spec)

    Consider adding an axiomatic triple as follows:
    rdfs:member rdf:type rdfs:ContainerMembershipProperty

By so doing, we have:
* rdfs:member is an instance of rdfs:ContainerMembershipProperty (not just rdf:Property) that is a super-property of all the container membership properties.
* Container membership properties must be applied to containers.

These reflects most of the intended meanings or use cases. Of course, the current treatment is not wrong. (See section 5.1.5, section 5.1.6  and Appendix A of the RDF Schema Spec, section 3.3 of the RDF Semantics spec)

2. About rdf:_nnn  (section 3.2.2 of the RDF Semantics spec)

Please consider adding one more example to clarify the meaning of rdf:_nnn, such as the following:

_:xxx rdf:type rdf:Seq.
_:xxx rdf:_2 <ex:a> .
_:xxx rdf:_2 <ex:c> .

<ex:a> and <ex:c> should denote the same thing? In other words, the property rdf:_nnn should be a functional property? (I haven't found any explanation about this issue in the spec) 

Considering there are two RDF graphs, the first one contains:

<foo:aContainer> rdf:type rdfs:Container.
<foo:aContainer> rdf:_1 <ex:a> .
<foo:aContainer> rdf:_2 <ex:b> .

The second one contains:
<foo:aContainer> rdf:_1 <ex:b> .
<foo:aContainer> rdf:_2 <ex:a> .

How about merging the two RDF graphs?


Thanks for your concern!


Yuzhong Qu
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Dept. of Computer Science and Engineering
Southeast University, Nanjing 210096, P. R. China
Home Page: http://cse.seu.edu.cn/People/yzqu/en
Research Group: http://xobjects.seu.edu.cn
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Received on Sunday, 16 February 2003 11:02:00 GMT

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