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Re: model theory and literals

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Wed, 10 Oct 2001 20:28:05 +0100
Message-Id: <>
To: Pat Hayes <phayes@ai.uwf.edu>
Cc: w3c-rdfcore-wg@w3.org
Can I try to clarify what I think you're saying...

Different occurrences of a literal within a graph may map to different 
values, but that these mappings are fixed, and may not change when a 
different interpretation is used for the graph.


   [a Shoe] decimalSize [ a type:Integer ; rdf:value "10" ] ;
            sizeLabel   [ a type:String ;  rdf:value "10" ] .

The intent here is that the first occurrence is mapped to an integer, and 
the second to a string.

BUT, doesn't this depend in some way on the interpretation of type:Integer 
and type:String?


At 12:36 PM 10/10/01 -0500, Pat Hayes wrote:
>Peter, after my mini-epiphany during the telecon yesterday, I had an even 
>better one :-). I think that there is a very tiny, if unconventional, 
>change to the RDF MT which will allow it to accommodate smoothly to your 
>(or anyone else's) proposed treatment of literals: simply say (with some 
>explanatory prose :-) that the XL mapping is a fixed mapping from literal 
>TOKENS to literal values. That is, it allows one occurrence of 
><whatever>05</whatever> to denote an integer and another one to denote a 
>string, just as long as they each denote the same thing in every 
>interpretation. This allows both the case where every literal is simply a 
>string which denotes itself, and it also allows the extreme other case 
>where an elaborate external datatyping process assigns special values in 
>all sorts of ways. However, it does insist that each literal label token 
>has a fixed interpretation; it doesn't tolerate ambiguity of any 
>*particular* literal label. I don't want to allow that kind of ambiguity.
>This will leave entirely mysterious how anyone or anything could determine 
>what the actual denotation of any particular literal token actually is, of 
>course. That is assumed to be done somehow, but is outside the scope of 
>the MT itself.
>With this change in wording, the actual equations can remain as they are.
>Would that be sufficient flexibility for you, along with allowing IR to 
>consist of both resources and literal values, so that rdfs:Literal doesn't 
>force literal values to be resources?
>PS I'm cross-posting this to both groups in case anyone can see a fatal 
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Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
Received on Wednesday, 10 October 2001 15:38:18 UTC

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