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Re: datatypes and MT

From: Dan Connolly <connolly@w3.org>
Date: Fri, 02 Nov 2001 09:09:00 -0600
Message-ID: <3BE2B70C.C5E881E4@w3.org>
To: Pat Hayes <phayes@ai.uwf.edu>
CC: w3c-rdfcore-wg@w3.org, pfps@research.bell-labs.com
Pat Hayes wrote:
> Let me try to first summarize the MT changes that I managed to
> extract from the pfps/ph interchange

I object to this proposal entirely.

> For example, the following graph written in bnode-style:
> aaa bbb _:1 .
> _:1 rdf:value "345" .
> _:1 rdf:type xsd:integer .
> would be boiled down into:
> aaa bbb _:1:"345" .
> _:1 rdf:type xsd:integer .

Let's not muck up the model theory like this. Let's
keep it simple: abstract syntax:
		constants (URIs w/fragids)
		string literals
		bnodes (existentially quantified variables)
		term term term.
with the traditional interpretation structure
(with the IEXT() indirection trick).

That's it.

If we want to say "my shoe size is some
integer whose decimal representation is '10'", that's easy:

	:me :shoeSize _:x.
	_:x rdf:type :integer.
	_:x :decimalRep "10".

which can be written in RDF/xml 1.0 very easily:

	<rdf:Description rdf:about="#me">
            <integer decimalRep="10"/>

To fill in the details... let dt:
be the namespace of XML Schema primitive datatypes,
and let rdfs:str be a new property
that relates XML Schema datatype to strings;
it's unambiguous over each of the primitive datatypes;
in the case of dt:string, it's the identity relation.

	<rdf:Description rdf:about="#me">
            <dt:decimal rdfs:str="10"/>

I use rdfs:str rather than rdf:value because M&S 1.0
(and some dublin core documentation) suggest that
rdf:value is for some wierd sort of currying.
I'd be happy to revoke the crazy suggestion about
currying and say that rdf:value works ala
rdfs:str above... but note that some folks
in www-rdf-logic pointed out that rdf:value
sorta goes backwards: one would think
that the value of a numeral is a number,
but rdfs:str goes from numbers to numerals.

Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Friday, 2 November 2001 10:09:03 UTC

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