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Re: SWC out of sync on rdf:PlainLiteral

From: Jos de Bruijn <jos.debruijn@gmail.com>
Date: Thu, 04 Mar 2010 18:05:21 +0100
Message-ID: <4B8FE851.2080007@gmail.com>
To: Sandro Hawke <sandro@w3.org>
CC: RIF <public-rif-wg@w3.org>
So, do you propose to change (in Table 1):

Constant in the xs:string symbol space 	"literal string"^^xs:string

to:

Constant in the rdf:PlainLiteral symbol space 	"literal
string@"^^rdf:PlainLiteral

?

That would be fine for me.

Cheers, Jos

On 2010-03-04 14:11, Sandro Hawke wrote:
>> SWC doesn't map plain literals to anything. According to the RDF
>> semantics, plain literals without language tags are always mapped to
>> themselves, i.e., strings of unicode characters. Now, XSD specifies that
>> xs:string literals are also mapped to themselves, and thus they
>> correspond 1-to-1 to plain literals w/o language tags.
>> Now, it happens to and be the case that the value space of
>> rdf:PlainLiteral also includes all strings. Therefore, there is a
>> one-to-one correspondence between RDF plain literals and xs:strings of
>> the form "xyz", on the one hand, and rdf:PlainLiterals of the form
>> "xyz@", on the other.
> 
> I'm not talking about the value spaces or the semantics, just the
> syntactic correspondence in Table 1.  (In terms of the semantics, yes, I
> agree with everything you say above.)
> 
>     -- Sandro
> 
>>
>> Best, Jos
>>
>> On 2010-03-02 20:06, Sandro Hawke wrote:
>>> During the telecon today we looked at
>>>
>>>    http://www.w3.org/2005/rules/wiki/RDF_Combination_Constant_Equivalence_2
>>>
>>> and it seems that while that example is supported by the SWC, SWC isn't
>>> saying quite the right thing, here.  It says plain literals without
>>> language tags map to xs:string constants, but I think it would be better
>>> to map to rdf:PlainLiteral constants.  The difference is actually
>>> invisible to any entailment test (I think?  maybe it depends on the
>>> entailment regime?), so in a sense RIF doesn't care, but for interchange
>>> purposes is does matter.  In particular, SPARQL, when not doing
>>> entailment, will notice the difference.   
>>>
>>> Do you remember why it's xs:string now?
>>>
>>> This isn't a huge problem, but if there's no compelling reason not to
>>> change it, I think it's more correct to map to rdf:PlainLiterals.
>>>
>>>      -- Sandro
>>
>> -- 
>> Jos de Bruijn
>>   Web:          http://www.debruijn.net/
>>   LinkedIn:     http://it.linkedin.com/in/josdebruijn
>>   Skype:        josdebruijn
>>   Google Talk:  jos.debruijn@gmail.com
>>   Mobile phone: +43 660 313 5733

-- 
Jos de Bruijn
  Web:          http://www.debruijn.net/
  LinkedIn:     http://it.linkedin.com/in/josdebruijn
  Skype:        josdebruijn
  Google Talk:  jos.debruijn@gmail.com
  Mobile phone: +43 660 313 5733
Received on Thursday, 4 March 2010 17:06:00 GMT

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