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Re: Requirements for a possible "RDF 2.0"

From: Hammond, Tony <t.hammond@nature.com>
Date: Thu, 14 Jan 2010 15:27:20 +0000
To: Bernard Vatant <bernard.vatant@mondeca.com>, Toby Inkster <tai@g5n.co.uk>
CC: Chris Welty <cawelty@gmail.com>, semantic-web <semantic-web@w3.org>
Message-ID: <C774E858.21129%t.hammond@nature.com>

> But please don't kill blank nodes !

To kill bnodes would presumably create a requirement to name each and every
component of the graph ­ which seems onerous to say the least. Unless there
were something like global unnamed properties, i.e. ³knwon unknowns². Maybe
Rumsfeld was on to something:

    ³There are known knowns. These are things we know that we know. There
are known unknowns. That is to say, there are things that we now know we
don¹t know. But there are also unknown unknowns. These are things we do not
know we don¹t know.²



On 14/1/10 15:03, "Bernard Vatant" <bernard.vatant@mondeca.com> wrote:

> Hi all
> Agreed with many points said
> - Don't fix what is not broken
> - Get rid or let die obscure constructions such as bags and reification
> - Simplify, simplify, simplify :)
> But please don't kill blank nodes !
> My use case (not academic, used on a daily basis) is translation from a model
> to another using SPARQL CONSTRUCT. Such translations (but it is yet another
> story to be discussed in another thread) are a very powerful way to pass from
> a model to another, without mapping declarations or commitments from either
> side. 
> Exemple
> Graph 1 is a document data base using  foaf:Document class with Dublin Core
> attributes such as dcterms:creator and dcterms:subject
> Graph 2 is a data base of expertises using a ex:Expertise class with object
> properties ex:expert, ex:topic and ex:supportDocument
> I can construct instances of ex:Expertise in G2 out of instances of
> foaf:Document in G1, but I have no URI in G1 for those. So I need bnodes in my
> query, such as :
> CONSTRUCT { _:x  a  ex:Expertise.
>                       _:x   ex:expert  ?p.
>                       _:x   ex:topic   ?t.
>                       _:x   ex:supportDoc  ?d}
> WHERE       {  ?d   a  foaf:Document.
>                       ?d   dcterms:creator   ?p.
>                       ?d   dcterms:subject   ?t }
> Unless SPARQL provide ways to generate URIs on the fly for my ex:Expertise
> instances. But I don't think it does.
> Seems very specific, but think about it before killing bnodes. Or provide
> something similar w/o them.
> Bernard
> 2010/1/14 Toby Inkster <tai@g5n.co.uk>
>> On Wed, 2010-01-13 at 11:00 -0500, Chris Welty wrote:
>>> > I suppose we don't really need to discuss whether we should
>>> > investigate an "RDF 2.0", but rather what kinds of requirements
>>> > various RDF users have that they would like to be considered (I'd like
>>> > this thread to be less "+1" and "-1" messages, and more "I'd like to
>>> > see RDF support x...")
>> Adopt SPARQL's data model for all future Semantic Web standards -- for
>> all SW protocols and serialisations.
>> The major differences between SPARQL's data model and RDF are:
>>   * Explicit support for named graphs
>>   * Literal subjects
>>   * Blank node predicates
>> (Though it might be a good idea to phase out blank nodes.)
>> --
>> Toby A Inkster
>> <mailto:mail@tobyinkster.co.uk>
>> <http://tobyinkster.co.uk>

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Received on Thursday, 14 January 2010 15:27:58 UTC

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