W3C home > Mailing lists > Public > w3c-rdfcore-wg@w3.org > November 2001

Re: heading toward datatyping telecon

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Fri, 02 Nov 2001 11:06:52 +0000
Message-Id: <5.1.0.14.2.20011102110204.03a712e0@joy.songbird.com>
To: Brian McBride <bwm@hplb.hpl.hp.com>
Cc: Pat Hayes <phayes@ai.uwf.edu>, w3c-rdfcore-wg@w3.org
At 09:31 AM 11/2/01 +0000, Brian McBride wrote:

>>>Pat's proposal defines a type to be a mapping from a lexical space to a 
>>>value space.  That means that a hexadecimal integer is a different type 
>>>from a decimal integer.
>>
>>Obviously the datatype mappings are not the same, but the value spaces 
>>can be overlap or even be the same. We can make them rdfs:subclasses of 
>>one another if you like.
>
>
>Hmmm.  That would make them equivalent.  Its bending my head a little, but 
>they are not equivalent, so that sounds like trouble.

I think there are two uses of "data type" at work here:  Pat's document 
(and also XML schema datatypes, methinks) treats them as a lexical space, a 
value space and a mapping from lexical to value space.  The other common 
use, including typed logics, I understand to be set of values that can be 
denoted by a symbol for a value of that type;  i.e. the "value space" only.

I'm guessing that Brian's point is that conflating these ideas in RDF might 
be confusing, or otherwise unhelpful.

#g


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Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
<Graham.Klyne@MIMEsweeper.com>
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Received on Friday, 2 November 2001 06:18:51 EST

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