W3C home > Mailing lists > Public > www-rdf-interest@w3.org > November 2001

RDFS bug "A property can have at most one range property"

From: <tarod@softhome.net>
Date: Fri, 16 Nov 2001 15:50:54 GMT
Message-ID: <20011116155055.24898.qmail@softhome.net>
To: www-rdf-interest@w3.org

  Sorry, I think that's a problem of OIL, an inference problem, but I don't
understand why that should be considered in RDFS. When I specify some
domains I want to specify where I can add this property, the property date
should appear in document and event. I don't want to say that a object with
date is a document AND an event. I want to say that is one of both. 

  RDF should not know anything about inference, that's another problem.


>On the intended semantics of rdfs:domain, we believe that this should
>be changed to intersection semantics as well. The reason for this is
>exactly the same as TBL's argument about range restrictions. If you
>add a local domain restriction that says, for example, that the domain
>restriction on "ISBN-number" should be "book", then given the union
>semantics, this has no effect at all if elsewhere it has already been
>asserted that the domain restriction on "ISBN-number" is "document".
>If I assert rdfs:domain(p,s) and I know that p(y,x), then I should be
>able to assume rdf:type(y,s) in exactly the same way as with range:
>     rdf:type(y,s)   <= rdfs:domain(p,s)  & p(y,x)
>With union semantics, this cannot be inferred. In fact, given that you
>can't know about all the other domain restrictions that have been made
>"elsewhere", then rdfs:domain(p,s) becomes completely meaningless.
>To summarize, we agree with TBL's view that the current definitions of
>domain and range are lacking, and would propose to allow both to be
>used multiple times, using intersection semantics.
Received on Friday, 16 November 2001 11:25:59 UTC

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