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Re: incorporating datatypes into the MT

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Thu, 31 Oct 2002 09:57:10 +0000
Message-Id: <>
To: pat hayes <phayes@ai.uwf.edu>
Cc: w3c-rdfcore-wg@w3.org

I think there may be a difference between incorporating the principles of 
datatyping (yes) and assuming knowledge of all the datatypes used 

So, yes, it's important to define the concept of a datatype, and how it 
works in conjunction with literals but, I think, also to retain the idea 
that there is a basic form of entailment in which no knowledge of the 
datatype mappings is assumed, distinct from a datatyped entailment in which 
such knowledge is assumed.

E.g. in "basic" entailment:

    Jenny age "10"^^xsd:integer .

does not entail

    Jenny age "010"^^xsd:integer .

But in a xsd:integer-aware entailment (with knowledge that datatype 
xsd:integer maps "10" and "010" to the same value) one *can* draw the 

(Hoping this helps rather than confuses.)


At 10:19 PM 10/30/02 -0600, pat hayes wrote:

>Er..... guys, I need guidance. I was under the impression that our 
>editoral task included incorporating the various aspects of datatyping 
>into our various documents, and that rather than being a separate 
>appendix, as it were, to RDF, that datatyping was now to be fully 
>integrated into the main thread. In the context of the MT, this means that 
>datatyping is pretty much the first thing that gets mentioned, since one 
>needs it to define what a typed literal means, and one needs that in order 
>to state the basic triple semantics for RDF in section 1.5. In other 
>words, in the document I am now working on, there will be no such thing as 
>a non-datatyped interpretation: datatyping will be built into the very 
>foundation of the language. RDF will *include* datatyping.
>Recent messages from Dan C and Jeremy and Jos, however, have made me 
>realize that some of us apparently expect the MT to be structured rather 
>like it has been in the past, in that there would be a simple basic RDF 
>notion of interpretation which had no such built-in stuff, and datatyping 
>would be one of the later additions.
>So my question is, will incorporating datatyping into the basic RDF MT 
>cause anyone grief? In particular, will it break the proposed API designs 
>apparently being developed? Because if so, we have some hard thinking to 
>do. I really don't see how I can make sense of typed literals without 
>talking about datatypes and datatype mappings.
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Graham Klyne
Received on Thursday, 31 October 2002 05:12:01 UTC

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