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Re: Denotation of datatype values

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 17 Apr 2002 16:40:37 -0500
Message-Id: <p05101509b8e39bdb6088@[65.217.30.94]>
To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Cc: w3c-rdfcore-wg@w3.org
>At 04:06 PM 4/16/02 +0300, Patrick Stickler wrote:
>>  > [GK wanders over to the stake in the ground, and gives it a hard kick, to
>>>  make sure it's still firmly planted...]
>>
>>Was it? ;-)
>>
>>Was the kick to test if was firmly planted, or to ensure
>>that it remains firmly planted?
>
>Keeping an eye on it...
>
>>  >> But we have been asked, to a certain extent, to provide an answer
>>>>  that extends to the point of obtaining a datatype value unambiguously
>>>>  and reliably. The present MT does not bring users to that point.
>>>>  A datatyped literal pairing does -- insofar as it identifies a single
>>>>  value which is obtainable by an application which groks the datatype
>>>>  in question.
>>>
>>>  Having an rdfd:range [[or substitute current vocab]] associated with a
>>>  property tells you nothing about the denotation of an object of that
>>>  property.  I.e. it does nothing to help "obtaining a datatype value
>>>  unambiguously and reliably".  (I found that trying to make it do so leads
>>>  to contradictions.)
>>>
>>>  All it does is limit the allowable literals at the property's sharp end.
>>
>>I either don't fully follow you, or disagree (or both ;-)
>>
>>If RDF Datatyping cannot provide a consistent and unambiguous
>>interpretation resulting in a specific datatype value, then
>>we're just wasting our time.
>
>Well, maybe, but as I understand things according to Pat's last proposal:
>
>     Jenny age "10" .
>     age rdfd:range xsd:integer .
>
>Tells us _only_ that the thing denoted by the node at the sharp end 
>of "age" is the 2-character string "10".  Which is exactly what you 
>have in absence of the rdfd:range statement.
>
>As far as it goes, that's pretty clear and unambiguous.  But to 
>conclude that Jenny's age is defined by the number 10 would be to 
>draw upon information that is not sanctioned by the graph and its 
>model theory.

Right. In fact, it would strictly speaking be in contradiction to the 
content of the RDF. Jenny's actual age probably is ten, but Jenny's 
<ex:age> is *definitely* the string "10" according to this RDF. That 
is fixed and unambiguous no matter what the datatyping information 
is, and we should be clear about that.

Pat
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Received on Wednesday, 17 April 2002 17:40:40 EDT

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