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Re: Saying anything about anything: Comments on Harle & Fensel

From: Jonas Liljegren <jonas@paranormal.o.se>
Date: Wed, 05 Jan 2000 18:42:50 +0100
Message-ID: <3873829A.D9E1313E@paranormal.o.se>
To: RDF Intrest Group <www-rdf-interest@w3.org>
CC: Stefan Decker <stefan@db.stanford.edu>
subject: Re: Saying anything about anything: Comments on Harle & Fensel

Stefan Decker wrote:
> 
> Sure. The problem comes when properties describe a "role", which can
> be filled by different ranges for different classes.

...

> Instead one has to ensure that a property is unique for each domain
> (e.g. by adding a class-prefix), which is redundant
> (and this was the main point in the paper).
> (e.g. something like hasHumanChild, hasDogChild).
> 
> The problem is, that a property can only be used in one class, but is
> globally visible for all classes.

Many properties CAN be used with many classes.

You don't have to encode that the child of a human is a human. That
can be explicitly stated by the type of the child resource.

But if you want to differ between human childs and dog childs, then
you should add this to the property schema. hasHumanChild and
hasDogChild can be subClassOf hasChild.

It should not be considered redundant. In RDF, there is no
hasHumanChild property. The propertys real name could be something
like http://my.org/rdf/class/Human#hasChild. The label of this
property could be "has child", and the domain and range could be
http://some.other.org/rdf/class#Human. 

This would result in that the visibel property name would be "has
child", but the RDF application would know that the range is only
humans. And any application could gain the information that this is a
sub property of the well known (generic) 'hasChild' property, that it
know so well.


-- 
/ Jonas  -  http://paranormal.o.se/perl/proj/rdf/schema_editor/
Received on Wednesday, 5 January 2000 12:43:03 GMT

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