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Re: Tag-less literals and literals with empty tags

From: Jakob Voss <jakob.voss@gbv.de>
Date: Wed, 06 Jul 2011 13:38:07 +0200
Message-ID: <4E14491F.5090306@gbv.de>
To: public-esw-thes@w3.org
Antoine Isaac wrote:

>> Alan Ruttenberg wrote:
>> without a language tag it is a string, with a language tag it is a
>> pair of strings. The set of plain literals without language tags is
 >> *not* the set of pairs (string , "").

The set of pairs (string , "") is not RDF. This is like comparing an RDF 
Triple with a poem and asking whether two can be equal or not.

The RDF data model does not allow such thing as "an empty language tag", 
so it is fruitless to discuss about the meaning of it in context of RDF. 
The SPARQL specification contains explicitly "Note that the RDF data 
model does not include literals with an empty language tag.":
http://www.w3.org/TR/rdf-sparql-query/#func-lang

> But for other RDF syntaxes, it's maybe not so clear. And I'm not sure
> it's "so clear" even for the RDF/XML situation: digging this was
> painful. Whichever of the alternatives is right (a tag-less literal is
> equivalent to a literal with empty language tag, or not) an extra line
> in one of the RDF specs would be handy!

That's mixing apples and oranges. The RDF spec is clear - there are no 
empty language tags. The specifications of RDF syntaxes may less clear, 
but then it's the particular problem of a RDF syntax. By the way I would 
avoid any discussion about any RDF issues that refers to examples in 
RDF/XML, unless you talk about RDF/XML and only RDF/XML.

Jakob

-- 
Jakob Vo▀ <jakob.voss@gbv.de>, skype: nichtich
Verbundzentrale des GBV (VZG) / Common Library Network
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Received on Wednesday, 6 July 2011 11:39:00 GMT

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