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RE: RDF Datatyping Working Draft

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Fri, 5 Apr 2002 18:34:11 -0600
Message-Id: <p05101515b8d3f0923008@[65.217.30.94]>
To: "Jeremy Carroll" <jjc@hplb.hpl.hp.com>
Cc: w3c-rdfcore-wg@w3.org
>Sorry Pat I had skipped right over section 5 on my first speed-read :(, so I
>think probably misunderstood some of the intent.
>
>The picture in section 6.1.2 looks like RDF Model Theory without any
>datatyping.
>
>The picture in section 6.1.3 seems to have gone further than is licensed by
>section 5.

Yes, it can be read that way. I think we need to re-do this picture.

>In section 5, as I understand it, John and Judy get age 25 (the integer -
>assuming knowledge of the actual l2v mapping) whereas Jane has age "25" the
>string.

Right.

>My asserted non-monotonicity occurs when John, Judy and Jane all have the
>same age as in 6.1.3.
>
>Here's why.
>
>Consider:
>
><John> <ex:age> _:x .
>_:x <xsd:integer> "25" .
><Judy> <ex:age> _:y .
>_:y <rdfd:lex> "25" .
><ex:age> <rdfd:range> <xsd:integer> .
><Jane> <ex:age> "25" .
><foo> <bar> "25" .
><bar>  <rdfd:range> <xsd:string> .

So, when datatyped, John and Judy have age 25, but Jane has age "25", right?

>
>In the model theoretic interpretation with no datatyping (and tidy literals)
>this entails:
>
><Jane> <ex:age> _:a .
><foo> <bar> _:a .

Right.

>but not
>
><Jane> <ex:age> _:c .
><John> <ex:age> _:c .

True, since we don't know what those values are without the datatyping.

>In the datatyping interpretation (following the picture 6.1.3) this entails:
>
><Jane> <ex:age> _:c .
><John> <ex:age> _:c .

No, not Jane and John. If you had said John and Judy, yes. But Jane's 
age is a string, and John's is a number (when datatyped). I think 
this picture might be misleading.

>but not
>
><Jane> <ex:age> _:a .
><foo> <bar> _:a .

No, it does entail that. Why not? Even when datatyped, those values 
are both the string "25", so the common generalization still holds. 
Adding datatyping only checks that strings are in the proper lexical 
space, and maybe imposes an interpretation on a bnode linked by a 
rdfd:lex to a literal. It doesn't change the interpretation of the 
literal.

>quod erat demonstrandum
>
>Jeremy
>
>
>Jeremy:
>>  >
>>  >Section 6.1.2 RDF Model Theory Interpretation
>>  >http://www-nrc.nokia.com/sw/RDFDatatyping.html#ntoc_26
>>  >
>>  >and
>>  >
>>  >Section 6.1.3 RDF Datatyping Interpretation
>>  >http://www-nrc.nokia.com/sw/RDFDatatyping.html#ntoc_27
>>  >
>>  >are different.
>>


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Received on Friday, 5 April 2002 19:40:01 EST

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