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Re: Subjects as Literals, [was Re: The Ordered List Ontology]

From: Kingsley Idehen <kidehen@openlinksw.com>
Date: Fri, 02 Jul 2010 09:22:28 -0400
Message-ID: <4C2DE814.4060809@openlinksw.com>
To: Michael Schneider <schneid@fzi.de>
CC: Linked Data community <public-lod@w3.org>, Semantic Web <semantic-web@w3.org>
Michael Schneider wrote:
> Kingsley Idehen wrote:
>
>   
>> So why: Subject-Predicate-Object  (SPO) everywhere re. RDF?
>>
>> O-R-O reflects what you've just described.
>>
>> Like many of the RDF oddities (playing out nicely in this thread), you
>> have an O-R-O but everyone talks about S-P-O.
>>
>> "Subject" has implicit meaning, it lends itself to describing stuff.  If
>> I recall, RDF stands for: Resource Description Framework.
>>
>> I guess "Description" also means nothing?
>>     
>
> "S-P-O" typically refers to a syntactic aspect of RDF triples, while "O-R-O"
> refers to a semantic aspect.
>
> "S-P-O": "S" ("subject") stands for the first node in an RDF triple. "P"
> ("predicate") for the second node. "O" ("object") for the third node. The
> nodes and the triples are entities of the RDF Abstract Syntax. They don't
> have any semantic meaning on their own.
>
> "O-R-O": In the RDF semantics, a syntactic RDF triple is interpreted as a
> relationship that holds between two individuals. The two "O"s refer the two
> individuals (or resources, or objects), being taken from the domain of
> discourse (the "world", about which assertions are made). The "R" stands for
> the property (or relation; in any case a semantic entity) that is used to
> define the relationship between the two individuals. 
>
> So, these are very different aspects that must not be confused. An "S-P-O"
> syntactic RDF triple is interpreted as a "O-R-O" semantic relationship
> between individuals. The "S" in "S-P-O" can be a URI, a bNode, and maybe
> also a literal in the future. The "O"s in "O-R-O" stand for entities in the
> "world". A semantic interpretation function can then use the "S" to denote
> (to "name") the "O". But there is no a-priory connection between the two:
> any "S-P-O" triple can be interpreted by any "O-R-O" relationship.
>
> I think, the main confusion comes from the use of the term "object" for two
> entirely different things: In the case of "O-R-O", it refers to (semantic)
> individuals. In the case of "S-P-O", it refers to a position in a
> (syntactic) RDF triple.
>   

Conflation Conflation. It makes RDF a real PITA, unfortunately.


EAV model is crystal clear:

Entity-Attribute-Value.

Slap on HTTP names for Entity, Attribute, and Value, optionally,  and 
you get an HTTP based World Wide Web of Structured Linked Data.


This is why conflating RDF and Linked Data has nothing but downside IMHO.


Kingsley
> Michael
>
> --
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> Research Scientist, Information Process Engineering (IPE)
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>   


-- 

Regards,

Kingsley Idehen	      
President & CEO 
OpenLink Software     
Web: http://www.openlinksw.com
Weblog: http://www.openlinksw.com/blog/~kidehen
Twitter/Identi.ca: kidehen 
Received on Friday, 2 July 2010 13:22:57 UTC

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