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Re: simplified datatyping proposal

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Wed, 20 Feb 2002 11:41:12 -0600
Message-Id: <p05101426b8998b8838f4@[65.212.118.219]>
To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Cc: w3c-rdfcore-wg@w3.org
>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....

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" .

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.

Pat
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Received on Wednesday, 20 February 2002 12:41:12 EST

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