Re: Everything is a Resource

On Oct 28, 2010, at 8:00 AM, Jakub Kotowski wrote:

> Hello Svatopluk,
> 
> Am 26.10.2010 00:47, schrieb Svatopluk Šperka:
>> There are rules rdfs4a and rdf4b which state that subject and object of
>> every triple are resources.
> Not really of every triple. You have to take into account the convention
> stipulated at the beginning of Section 7:
> 
> "These rules all use the following conventions: aaa, bbb, etc., stand
> for any URI reference, i.e. any possible predicate of a triple; uuu,
> vvv, etc. for any URI reference or blank node identifier, i.e any
> possible subject of a triple; xxx, yyy etc. for any URI reference, blank
> node identifier or literal, i.e. any possible subject or object of a
> triple; lll for any literal; and _:nnn, etc., for blank node identifiers."
> 
> i.e. rules rdfs4a and rdfs4b exclude literals.

They do so because to put literals in these positions in the rules would violate the RDF *syntax* condition that a subject of a triple cannot be a literal. However, this is an arbitrary syntactic condition (imposed to keep the XML simple) and has no semantic significance.

> Literals simply are not
> of type rdfs:Resource according to the current specification.

Literals are part of the RDF syntax. But the literal values that they denote are indeed of rdf:type rdfs:Resource. In a nutshell, anything that any RDF 'name' (blank node, UIR or literal) can denote is an element of rdfs:Resource. 

Pat Hayes

> There's a
> long thread about a closely related problem on this mailing list:
> 
> http://lists.w3.org/Archives/Public/public-lod/2010Jun/thread.html#msg309
> 
> 
>> These rules seem to me as special cases of rdfs2 and rdfs3 which are
>> saying that subject/object of a triple can be assinged a type according
>> to defined domain/range of a property in a triple. Only condition is
>> that It would have to be given that for every property, its domain and
>> range is class of all resources.
> ... which is not true, see above.
> 
> Regards,
> Jakub
> 
> 
> 

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Received on Thursday, 28 October 2010 14:01:23 UTC