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Where DAML+OIL deviates from the RDF-Schema spec.

From: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
Date: Sat, 24 Feb 2001 23:53:09 +0100
Message-ID: <3A983B55.88AAD444@cs.vu.nl>
To: www-rdf-logic@w3.org
The newly announced Semantic Web activity of the W3C will include an RDF Core working group which will revise and finalise the RDF/RDF-Schema specs. The following is intended as input to that working group. 

They are quotes from the DAML+OIL reference doc at  
http://www.daml.org/2000/12/reference.html

I believe this to be a complete list of all ways in which DAML+OIL (intentionally) violates the RDF-S
spec.

[1]
"Warning: The RDF Schema specification demands that the subclass-relation between classes
must be acyclic. We believe this to be too restrictive, since a cycle of subclass
relationships provides a useful way to assert equality between classes. Consequently,
DAML+OIL places no such restriction on the subClassOf relationship between classes;"

[2]
"[in DAML+OIL] multiple domain expressions restrict the domain of P to the intersection of
the class expressions. 
Warning: This is contrary to the semantics of the domain element in the RDF Schema
specification, which we believe to be flawed."

[3]
"Warning: Although the RDF Schema specification only allows one range restriction for each
property, it seems quite natural to allow multiple range restrictions. These would then
again be interpreted as saying that the range of P must be the intersection of all the
class expressions."

Frank.van.Harmelen@cs.vu.nl              http://www.cs.vu.nl/~frankh
Department of AI, Faculty of Sciences,  Vrije Universiteit Amsterdam
de Boelelaan 1081a, 1081HV Amsterdam, The Netherlands
tel (+31)-20-444 7731 fax&voicemail (+31)-20-8722806
Received on Saturday, 24 February 2001 17:55:10 GMT

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