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Re: proposal: Structured Datatypes

From: Jonathan Borden <jonathan@openhealth.org>
Date: Wed, 6 Nov 2002 22:16:18 -0500
Message-ID: <005e01c2860c$0c8d6dc0$7c674544@ne.mediaone.net>
To: <connolly@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <www-webont-wg@w3.org>

Peter F. Patel-Schneider wrote:
>
> Unfortunately, there are several problems with this approach, aside from
> the problem that Dan has identified.
>
> First, the RDF, and thus the OWL, meaning for XML Schema built-in types is
> incompatible with this meaning.  Second, XML literals in RDF are just
> literals, not anything else, so there is very limited utility in the
> scheme.  For example, if the element "a" had type int, <a>010</a> and
> <a>0010</a> would be different.

That is the whole point of this. Given the above datatype, and if the
property is defined as functional the following entailment would hold:

ex:foo ex:DTprop "<a>010</a><b>aaa</b>"^^rdfs:XMLLiteral
ex:bar ex:DTprop "<a>00010</a><b>aaa</b>"^^rdfs:XMLLiteral

=>

ex:foo owl:sameIndividialAs ex:bar

>...Third, this approach would preclude any
> attempt to do something better, like having the value above be a piece of
> semi-structured data, containing an int and a string.
>

I don't follow, this approach is exactly intended to allow an XML Literal to
be interpreted as semi-structured (or structured) data, in this case
containing an int, and string.

That is the whole point, the range of a datatype property is used to provide
an interpretation of the XML Literal, as more than just simple XML (or a
base XML infoset) but rather as a PSVI i.e. type adorned infoset.

Now it would have been easier for WebOnt if RDFCore had simply allowed:

"<a>123</a><b>aaa</b>"^^http://example.org#xType

but that idea got shot down by RDF Core.

Jonathan
Received on Wednesday, 6 November 2002 22:35:51 GMT

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