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Re: SWC out of sync on rdf:PlainLiteral

From: Jos de Bruijn <jos.debruijn@gmail.com>
Date: Fri, 05 Mar 2010 08:56:06 +0100
Message-ID: <4B90B916.8080900@gmail.com>
To: Sandro Hawke <sandro@w3.org>
CC: RIF <public-rif-wg@w3.org>
I implemented the change on the Wiki. If anyone objects to the change
please speak up.


Cheers, Jos

On 2010-03-04 18:30, Sandro Hawke wrote:
>> 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
>>
>> ?
> 
> Exactly.   Also, a few lines down, there's a bullet:
> 
>    * Strings, i.e., constants of the form "my string"^^xs:string may be
>      written as "my string".
> 
> which would be changed to:
> 
>    * Plain literals without language tags, i.e., constants of the form
>      "my string@"^^rdf:PlainLiteral may be written as "my string".
> 
> Which makes me wonder what other specs, if any, that affects, and what
> Hassan & Stella's code does.  Basically, that affects the mapping from
> Presentation Syntax to XML Syntax.
> 
>> That would be fine for me.
> 
> Good...
> 
>      -- Sandro
> 
>> 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

-- 
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 Friday, 5 March 2010 07:56:47 GMT

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