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Re: RDF Issue rdfms-literalsubjects

From: Tim Berners-Lee <timbl@w3.org>
Date: Thu, 21 Feb 2002 15:50:59 -0500
Message-ID: <00eb01c1bb19$f36c92c0$ef001d12@CREST>
To: "Brian McBride" <bwm@hplb.hpl.hp.com>
Cc: <www-rdf-comments@w3.org>
Brian,

I understand that current RDF does not allow subjects to be literals.
This is acceptable as a response at this stage, because of the damage to the
RDF
syntax to try to fix it.

I am happy that the group sees no reason to keep the restriction in future
versions.

As a user, I would like to see a plan for a new version
of RDF with this restriction removed.   I suggest the working group prepare
a list of requirements for such future work to make such rechartering
easier,
and that this be on them.

It might be nice to make some indication that this may be done in the future
so that systems don't code the restriction in deep down.


To clarify, The problems I have with it are.

1)  It is an arbitrary restriction, destroying symmetry for no reason.
Therefore it is aesthetically bad.

2)  Practically, there are lots of times when, during processing, statements
may be generated
   which have literal subjects.  This means that, for example, RDF is not
complete with a notion
  of inverse.   (e.g. :date string:greaterThan "2000"   <->  "200"
string:noGreaterThan  :date >

3) The inconsistency shows up in many ways.  The resolution of a query can
end
  up substituting in a literal where logic says it is allowed

In my own code I really have not the time or energy to code in this
arbitrary restriction,
so I have to simply stick to N3 for outputting things where this might
happen.

4) It is actually useful sometimes to write things about strings.

        "chat"    lang:inFrenchInEnglishIs "cat".

to be simplistic.

Tim


----- Original Message -----
From: "Brian McBride" <bwm@hplb.hpl.hp.com>
To: <timbl@w3.org>
Cc: <www-rdf-comments@w3.org>
Sent: Monday, February 18, 2002 11:41 AM
Subject: RDF Issue rdfms-literalsubjects


> Tim,
>
> In
>
>    http://lists.w3.org/Archives/Public/www-rdf-interest/2000Feb/0172.html
>
> you raised an issue which was captured in
>
>    http://www.w3.org/2000/03/rdf-tracking/#rdfms-literalsubjects
>
> as
>
> [[[
> Should the subjects of RDF statements be allowed to be literals?
> ]]]
>
> As recorded in
>
>    http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2002Feb/0476.html
>
> the RDFCore WG has decided to close this issue:
>
> o  the WG resolves that the current syntaxes
>     (RDF/XML, n-triples, graph syntax) do not
>      allow literals as subjects.
>
>    o the WG notes that it is aware of no
>      reason why literals should not be subjects
>      and a future WG with a less restrictive
>      charter may extend the syntaxes to allow
>      literals as the subjects of statements.
>
> Please could you respond to this message, copying www-rdf-comments@w3.org
> indicating whether this is an acceptable resolution of this issue.
>
> Brian McBride
> RDFCore co-chair
>
Received on Thursday, 21 February 2002 15:55:17 GMT

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