Pat Hayes wrote:
>> Pat Hayes wrote:
>>>> Re: Peter F Brown's post (2007年4月14日 09:35:14)
>>>>
>>>> Peter writes:
>>>>
>>>> "
>>>> The spec is clear, yesS. but an object is not the same thing as the
>>>> address of the object - (according to the RFC, I *am* my address): the
>>>> object needs identity as much as the address of it does. That is
>>>> where I
>>>> feel this axiom of the W3C falls downS
>>>> "
>>>>
>>>> Clearly there is a problem here. But we should be careful to
>>>> distinguish confusedly designed frameworks from confused documentation
>>>> of well-designed ones.
>>>>
>>>> While RDF specifications, for example, are relatively clear and sound,
>>>> the RDF primer provides an abundance of examples such as:
>>>>
>>>> ex:index.html exterms:creation-date "August 16, 1999" .
>>>> ex:index.html dc:language "en" .
>>>>
>>>> supposed to state that "August 16, 1999" is the creation date of a
>>>> page
>>>> and "en" is he language of a page, while both are literal strings and
>>>> *not* identifiers for a date and a language, respectively.
>>>
>>> What?? Why should a string not be an identifier? In fact, it seems to
>>> me that *all* identifiers are strings. And the second example uses a
>>> language tag which is taken from an Internet standard for language
>>> tagging: what could be a better example of an agreed identifier? Why is
>>> this confused?
>>
>> Hold on. It is not whether something is a string or not which counts,
>> but how it is to be interpreted. Of course, "August 16" can be an
>> identifier for anything you may wish. But it is a string, not a date.
>
> Of course it is not a date, but it is (using widely accepted
> conventions) an *identifier* of a date.
>
>> But as the object of a triple, "August 16" is a literal, not a URI, and
>> in RDF, a literal is (supposed to be) self-referential.
>
> True. But it is an easy extension to the RDF interpretation to go on to
> interpret that string as denoting a date. RDF was always intended to be
> used as part of larger systems of conventions and interpretations. (01)
Agreed. But then the discussion of whether a URI means itself or
something else is also left to other applications, and any complaint
should be sent there. (02)
>
> And this is, after all, an example from a primer. The best way to
> express this in RDF would be to use a typed literal with the xsd:date
> system, which is required to exactly denote a date; but the primer had
> not covered datatyping at this point. (03)
It did, of course. (The 2004 version does speak of xml-schema datatypes.) (04)
vQ (05)
>
> Pat (06)
--
Wacek Kusnierczyk (07)
------------------------------------------------------
Department of Information and Computer Science (IDI)
Norwegian University of Science and Technology (NTNU)
Sem Saelandsv. 7-9
7027 Trondheim
Norway (08)
tel. 0047 73591875
fax 0047 73594466
------------------------------------------------------ (09)
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