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Re: Datatype Confusion

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Tue, 04 Feb 2003 09:50:25 -0500 (EST)
Message-Id: <20030204.095025.28494774.pfps@research.bell-labs.com>
To: Volz@fzi.de
Cc: www-webont-wg@w3.org

From: "Raphael Volz" <volz@aifb.uni-karlsruhe.de>
Subject: AW: Datatype Confusion
Date: Tue, 4 Feb 2003 14:25:03 -0000

> Hi -
> 
> while trying to come up with the OWL API I stumbled over
> the data type stuff and found several serious inconsistencies
> in the document.
> 
> (A)
> OWL Reference document states: ( Sec 7.1 )
> 
> OWL makes use of the RDF datatyping scheme, refers to [RDF Concepts,
> http://www.w3.org/TR/2002/WD-rdf-concepts-20021108/ ]
> which states (Sec 2.2.5) that
> "RDF can use values represented according to XML schema
> datatypes [XML-SCHEMA2]"
> --> This would allow for Complex Datatypes

I suggest you send in a message to www-rdf-comments@w3.org concerning this
problem with RDF.  Meanwhile, the reference document should be careful how
it discusses this issue.

> (B)
> OWL Guide Draft states: (
> http://www.w3.org/2001/sw/WebOnt/guide-src/Guide.html )
> (3.2.2. Properties and Datatypes)
> 
> "OWL uses some of the defined, non-list XML Schema datatypes. "
> what is non-list datatypes. This is proprietary terminology. Does
> non-list mean, primitive datatypes only ? The intended meaning
> may be understood after reading the appropriate section in
> http://www-db-out.bell-labs.com/user/pfps/owl/semantics/syntax.html#owl-data
> types
> I would advise to include this into the guide and say, that
> we are dealing with a subset of XML Primitive Datatypes, namely
> those depicted in the attached figure.



> (C) OWL AS+S
> http://www-db.research.bell-labs.com/user/pfps/owl/semantics/syntax.html#owl
> -datatypes
> Took this as normative. Maybe give the appropriate section a title
> and include figure.
> I wonder how OWL can be fully compatible with RDF semantics if
> RDF allows for the complete XMLS type system (including primitve list and
> complex types)...

Actually, the AS&S is compatiable with the part of the RDF semantics that
deals with datatypes.  (I may have to make a final pass to ensure
compatibility of terminology.)  At least it is compatible with the part of
the RDF datatype semantics that makes sense.  I have sent in a note to
www-rdf-comments indicating that, for example, the XML Schema datatype
QName is not suitable as an RDF datatype.  Pat Hayes is still in denial
over this, perhaps Jeremy Carroll could continue the discussion, as he
noticed the problems with these XML Schema datatypes.

However, AS&S should change to 
	The following built-in XML Schema datatypes ....
As XML Schema doesn't use ``list'', it uses ``sequence''.  In any case, the
only ``sequence'' XML Schema built-in datatypes are sequences of datatypes
that don't make sense for OWL (or RDF).  I've just made this editorial
change.

> (D) Web Ontology Language (OWL) Test Cases (http://www.w3.org/TR/owl-test/)
> No datatype related tests...
> 
> 
> Mit freundlichen Gru?en,
> Best regards,
> 
> Raphael Volz
> Institut AIFB, Universitat Karlsruhe
> http://www.aifb.uni-karlsruhe.de/WBS/rvo
> volz@aifb.uni-karlsruhe.de
> 
> WIM, FZI Karlsruhe
> http://wim.fzi.de/
> volz@fzi.de
> 
> Fax: 01212-5-470-17-365
Received on Tuesday, 4 February 2003 09:50:35 GMT

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