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What is RDF Datatyping?

From: Patrick Stickler <patrick.stickler@nokia.com>
Date: Thu, 18 Apr 2002 16:37:04 +0300
To: RDF Core <w3c-rdfcore-wg@w3.org>
Message-ID: <B8E4A6B0.135CB%patrick.stickler@nokia.com>

Please read the following carefully and possibly several times
before blasting away at it. Thanks.


I assert that the following are true and should be captured by the
RDF Datatyping specification:

1. The purpose of RDF Datatyping is to exchange knowledge containing
datatype values.

2. The means by which RDF Datatyping captures knowledge about
datatype values is by associating lexical forms (literals) with
datatypes (URIrefs).

2. A datatyping idiom is an expression of a datatyped value which
associates a lexical form with a datatype, and
is comprised of (a) a literal, taken to be a lexical form, (b) a
URI, taken to identify a datatype, and optionally (c) a blank node
which denotes the datatype value represented by the lexical form
according to the lexical to value mapping of the specified datatype.

3. A literal which occurs as part of a datatyping idiom always
denotes itself, the string, even though it is also understood to
represent a datatype value in conjunction with the specified
datatype. This is not a contradiction. The literal by itself
cannot identify a datatype value. It is only the combination
of the literal and datatype which provide sufficient information
to identify a datatype value.

4. The value denoted by a blank node occurring as part of a lexical
form or datatype property idiom is unknown to RDF. It can only be
known externally to RDF with the addition of full knowledge of the
datatype mapping. Thus, datatype clashes cannot occur within RDF.

I consider sections 2-4 of the datatyping WD to capture these truths.
Whether the terminology used is optimal, or whether the concept of
datatyped literal pairings is acceptable or not, and whether it
remains or is removed, is a separate matter. I am happy to
rephrase those sections to the satisfaction of the WG, or allow
any other WG member to do so, but I consider the above truths
to hold and will expect any rewording of the datatyping specification
to reflect them.

If the datatyping MT in section 5 does not fully capture the above,
then I consider it to be either incorrect, or incomplete.

Of course, the WG is free to correct me on any of the above if
it does not reflect a majority view.


Patrick Stickler              Phone: +358 50 483 9453
Senior Research Scientist     Fax:   +358 7180 35409
Nokia Research Center         Email: patrick.stickler@nokia.com
Received on Thursday, 18 April 2002 14:24:53 UTC

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