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Re: ContainerMembershipProperty

From: Aaron Swartz <aswartz@swartzfam.com>
Date: Thu, 31 May 2001 20:45:31 -0500
To: Mark Birbeck <Mark.Birbeck@x-port.net>, RDF Comments <www-rdf-comments@w3.org>
Message-ID: <B73C5DE9.CCC3%aswartz@swartzfam.com>
Mark Birbeck <Mark.Birbeck@x-port.net> wrote:

>   <rdfs:Class rdf:ID="ContainerMembershipProperty">
>       <rdfs:subClassOf
> rdf:resource="http://www.w3.org/1999/02/22-rdf-syntax-ns#Property" />
> *->     <rdfs:domain rdf:resource="#Container" />
>   </rdfs:Class>

Good question -- the answer is no, it's not a mistake, but for some
interesting reasons.

First, you can't put a domain property on a class. What you really want to
say is that all members of the class have that domain, but RDFS isn't
expressive enough to say that.

Second, RDF (which defines the container properties) never says that they
must be used on containers. In fact, "A Proposed Interpretation of RDF
Containers"[1] depends on this fact.

[1] http://www-uk.hpl.hp.com/people/bwm/rdf/issues/containersyntax/

In conclusion, there appears to be nothing wrong with attaching ordinal
properties to an average resource. However, there are a number of problems
with containers and the RDF Core WG is currently looking into them. Feel
free to submit any suggestions or comments you might have to this list.

[ Aaron Swartz | me@aaronsw.com | http://www.aaronsw.com ]
Received on Thursday, 31 May 2001 21:45:42 UTC

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