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Re: Subjects as Literals

From: Antoine Zimmermann <antoine.zimmermann@deri.org>
Date: Tue, 06 Jul 2010 22:27:29 +0100
Message-ID: <4C339FC1.9040002@deri.org>
To: nathan@webr3.org
CC: Pat Hayes <phayes@ihmc.us>, Toby Inkster <tai@g5n.co.uk>, Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
So to clarify a bit:

A serialisation is just a way to write down an RDF document in a 
computer. A serialisation of RDF must respect the abstract RDF syntax, 
which forbids literals in subject position. If the serialisation allows 
literals as subject, it is not a serialisation of RDF but it serialises 
a more general language (e.g., N3).
Then comes the semantics. The semantics does not allow or disallow 
anything, it just provides a notion of interpretation of an RDF 
vocabulary, and a notion of satisfaction of an RDF document (which must 
*not* have a literal in subject position). However, what we mean by 
saying, informally, that "the semantics allows literals in subject" is 
that the very same semantics could be applied to generalised RDF.

So, strictly speaking, no, the semantics does not allow you to put 
literals in subject, but it allows you to straightforwardly define the 
possible meaning of a generalised triple.


AZ

Le 06/07/2010 22:02, Nathan a écrit :
> Pat Hayes wrote:
>> However, before I lose any more of my SW friends, let me say at once
>> that I am NOT arguing for this change to RDF.
>
> so after hundreds of emails, I have to ask - what (the hell) defines RDF?
>
> I've read that 'The RDF Semantics as stated works fine with triples
> which have any kind of syntactic node in any position in any combination.'
>
> Do the 'RDF Semantics' define RDF? or do the serializations?
>
> simply - does RDF support literal subjects or not - I've read the
> aforementioned sentence to read 'RDF Semantics support literal subjects'
> or should I be reading 'RDF Semantics could support literal subjects' or
> 'does support literal subjects' or?
>
> Just seeking a definitive bit of clarity on 1: what defines RDF, 2: what
> is *currently* supported in that definition.
>
> Preferably a serialization unspecific answer :)
>
> Best & TIA,
>
> Nathan
>
Received on Tuesday, 6 July 2010 21:28:03 UTC

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