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Re: Denotation of datatype values

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 17 Apr 2002 16:50:39 -0500
Message-Id: <p0510150ab8e39c82877e@[65.217.30.94]>
To: Patrick Stickler <patrick.stickler@nokia.com>
Cc: w3c-rdfcore-wg@w3.org
>On 2002-04-16 18:56, "ext Graham Klyne" <Graham.Klyne@MIMEsweeper.com>
>wrote:
>
>
>>>  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.
>
>I'm not saying otherwise.
>
>>  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.
>
>But I'm not saying that. I'm saying that the combination of the
>inline idiom and the rdfd:range/datatype assertion designates
>the pairing <xsd:integer, "10"> and that pairing is the basis
>for any datatyping interpretation.

Right, and please DONT say that because that is WRONG. Or else it is 
meaningless (I'm not sure what 'designates' means, but certainly 
those pairs are not the basis for a datatyping interpretation in the 
current MT. If you want to change the MT so as to introduce them, 
then go ahead and try, but I fear for your sanity. Getting this far 
drove me batty. )

>I.e., the knowledge in the
>graph unambiguously identifies a single value

Of course the value is there in the value domain, in some Platonic 
sense. But the graph doesn't always refer to, or say anything about, 
that value. In particular, the inline idiom does not refer to it in 
any way.

>by designating
>a datatyped literal pairing. What that actual
>value is, we don't know *at this level*. But at a higher level
>where the full knowledge of xsd:integer is available, then
>we know that the pairing <xsd:integer, "10"> identifies the
>value ten.

It also 'identifies' membership in a lexical domain (in the inline 
idiom), membership in a value domain (if you use that uriref as a 
class name in a rdfs:range assertion, for example) and a particular 
lexical-to-value mapping (if you use it as a property name). It can 
identify all these things, and maybe more besides. That is why we 
need so many idioms.

>
>The RDF Datatyping MT is not saying the value is ten. It is
>saying that it is whatever value is identified by the interpretation
>of the lexical form "10" within the context of the datatype
>xsd:integer.

No, it isn't saying that. It doesn't refer to contexts, and it is not 
saying that the lexical form identifies a value. That is a very 
misleading and confusing way to describe what the MT says, since the 
MT says very clearly that any literal denotes a string, even when it 
is 'associated' with a datatype, and even in the 'context' of a 
datatyping interpretation.

>That may seem like a very slight distinction, but it is
>a very significant one.

I agree it is significant, which is why I would like to get it right.

Pat

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Received on Wednesday, 17 April 2002 17:50:43 EDT

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