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Re: plain literals without language tag compare xsd:string in RDF

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Sat, 8 Mar 2008 10:06:00 -0500
Message-Id: <09A75DC4-624C-4D0B-A7C8-1B2C1178D03C@gmail.com>
Cc: Pat Hayes <phayes@ihmc.us>, "public-awwsw@w3.org" <public-awwsw@w3.org>, "Carroll, Jeremy John" <jeremy.carroll@hp.com>
To: "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>

This would seem to be at odds with the RDFS documentation:

6.5.1 Literal Equality
Two literals are equal if and only if all of the following hold:

  - The strings of the two lexical forms compare equal, character by  
character.
  - Either both or neither have language tags.
  - The language tags, if any, compare equal.
  - Either both or neither have datatype URIs.
  - The two datatype URIs, if any, compare equal, character by  
character.

In this case, the 4th clause is violated.

-Alan

On Mar 7, 2008, at 10:31 AM, Williams, Stuart (HP Labs, Bristol) wrote:

> Alan,
>
> I raised you question with my colleague, Jeremy Carrol (Cc'd) who  
> responded as follows:
>
> <quote>
> They are identical
>
> "foo" owl:sameAs "foo"^^xsd:string .
>
> is necessarily true.
>
> http://www.w3.org/2000/10/rdf-tests/rdfcore/datatypes/test011a.nt
> entails
> http://www.w3.org/2000/10/rdf-tests/rdfcore/datatypes/test011b.nt
> as recorded in the RDF Test Cases doc
>
> Jeremy
> </quote>
>
> In a further exchange he also confirmed/clarified that it is  
> neccessarily the case that:
>
>         "1234" owl:sameAs "1234"^^xsd:string .
>
> ie. (I think) that means that:
>
>         "1234" owl:sameAs "1234"^^xsd:integer .  ## or some other  
> numeric datatype.
>
> is necessarily false (which is what I would expect).
>
> Cheers,
>
> Stuart
> --
> Hewlett-Packard Limited registered Office: Cain Road, Bracknell,  
> Berks RG12 1HN
> Registered No: 690597 England
>
>
>> -----Original Message-----
>> From: public-awwsw-request@w3.org
>> [mailto:public-awwsw-request@w3.org] On Behalf Of Alan Ruttenberg
>> Sent: 04 March 2008 15:29
>> To: Pat Hayes
>> Cc: public-awwsw@w3.org
>> Subject: plain literals without language tag compare xsd:string in  
>> RDF
>>
>>
>> Is there any utility to having these being disjoint classes?
>> It would seem to me that it would be more sensible to say
>> that any string that doesn't have a  language type or a
>> datatype is inferred to be of type xsd:string.
>>
>> Did this situation come about because it was easier to make
>> the RDF semantics look cleaner, or was there some principled
>> reason for making the distinction?
>>
>> -Alan
>>
>>
>>
Received on Saturday, 8 March 2008 15:06:26 GMT

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