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Re: simplified datatyping proposal

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 20 Feb 2002 21:23:06 -0600
Message-Id: <p05101401b89a14505289@[65.212.118.219]>
To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Cc: w3c-rdfcore-wg@w3.org
>At 11:41 AM 2/20/02 -0600, Pat Hayes wrote:
>>>Oh dear, it's looking as if I seriously dropped the ball on this...
>>>
>>>With my CC/PP hat on I don't see the following "long-range" usage 
>>>is supported:
>>>
>>>    _:SomeClientComponent client-property:dpi "100" .
>>>
>>>     :
>>>
>>>    client-property:dpi rdfs:range datatype:number .
>>>
>>>i.e. does not define support for idiom B in the datatyping 
>>>desiderata document:
>>>
>>>
>>>http://lists.w3.org/Archives/Public/www-archive/2002Jan/att-0133/00-gk.htm
>>>
>>>What also now seriously bothers me is that I can't see how the 
>>>full proposal [1] supports this either.  I had earlier convinced 
>>>myself that this was all OK, but now I can't see it.   Aaargh!
>>
>>No, it definitely does not support it, in fact in its current form 
>>it effectively deprecates it, since literals always denote 
>>themselves, and there is no way to change the meaning of an in-line 
>>literal. But I thought that was what we had all decided to do?? The 
>>proposals have been saying this loud and clear in paragraph 1 from 
>>the beginning, and people were sending me only positive comments, 
>>so....
>
>Yeah... I don't know how I missed it...  I guess I've been looking 
>at so many proposals over the past couple of weeks I'm just not 
>seeing the wood for the trees.
>
>>To fix this, at the very least, you would have to use rdfs:drange 
>>instead of rdfs:range. Right now that would not work either, but I 
>>can tweak the semantics to make it work.  But at a cost: we have to 
>>allow  nonmonotonic datatyping, in the sense that adding an 
>>rdfs:drange assertion *alters* the interpretation of the in-line 
>>idiom. There's no way around that, seems to me. But maybe we can 
>>live with this much nonmonotonicity  when considering datatypes.
>>
>>Can I ask y'all for some clarification. Do people want to support 
>>BOTH in-line and bnode forms at the same time? That is, should the 
>>following mean the same thing and be affected in the same way by a 
>>drange assertion on ex:age ??:
>>(1)
>>person:Jenny ex:age "10" .
>>(2)
>>person:Jenny ex:age _:x .
>>_:x rdfs:dlex "10" .
>
>I think both have their place:  (1) is how CC/PP currently works, 
>but (2) provides a more flexible way of modelling going forwards.
>
>>As things are at present, (1) means that Jenny's age is a character 
>>string, no matter what else you say, whereas (2) says her age is 
>>something that can be described by a character string, so can be 
>>modified by other datatyping. We can change this, as I say, but 
>>only at a cost.
>
>I have no problem with that bit ... I just want to be able to say 
>that not all strings are valid here, only those which can represent 
>(in this case) Jenny's age.

AAARGH!!!  I wish you would say what it is you DO want. People keep 
contradicting themselves, no wonder we cant get to a resolution of 
this damnable issue.

I thought that the whole point of the B idiom was that it DID allow 
datatyping to alter the denotation of the literal. If CC/PP doesn't 
need that, we don't need to allow the inline idiom to be sensitive to 
datatypes.

Please will you say EXACTLY what you want to be able to do. Then I 
promise I will hit your target. But for Gods sake keep the target 
still for a while.

>  (It doesn't really matter to CC/PP what the "10" formally denotes, 
>but I don't want to avoid the possible conclusion that person:Jenny 
>ex:age "Humpty Dumpty" is equally meaningful.)
>
>Also, I don't think they have to be available for the same property, 
>though they may be needed for different properties in the same 
>graph;  e.g.
>
>    person:Jenny ex:age "10" .
>    person:Jenny ex:weight _:x .
>    _:x xsd:number "10" .
>
>(Did you mean to use rdfs:dlex in your example above?)

Yes, the point being that in both cases the datatyping information 
can come from 'outside', ie  by dranging ex:age.

Pat

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Received on Wednesday, 20 February 2002 22:23:10 EST

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