Re: resources (RDF, that is)

(top quoting 'cause I've contributed nothing beyond encouragement.)

Thanks for tackling this. I'd very much like to get our terminology
correct and act as a template for other specs. Your SPARQL point is
clear indication of the need to tighten up our vocabulary.


* Holger Knublauch <holger@topquadrant.com> [2014-12-18 10:10+1000]
> Yes I agree we need to be consistent with how other W3C specs are
> written, and the term "Resource" is unfortunately overloaded so it's
> best avoided.
> 
> When I have been using these terms here, I was considering them as
> technical entities as used for example in the Jena API, which uses
> the following class hierarchy
> 
> RDFNode
>    Literal
>    Resource
>        Property
> 
> From this angle, a node is the generalization of literals and
> resources. Whether the resources also happen to have a corresponding
> entity in the real world is off-topic from this POV. In this
> interpretation the term "node" means "either literal or resource"
> and the term "resource" excludes literals.
> 
> I am just saying this because I believe many other people consuming
> our documents will share the same interpretation. I see that the
> official specs use the term "Resource" to be the graph
> representation of either a literal or IRI, but not a blank node:
> 
>    http://www.w3.org/TR/rdf11-concepts/#resources-and-statements
> 
> which is indeed a very different interpretation than what for
> example the Jena or Sesame APIs do.
> 
> So moving forward, I believe the equivalent terms for the API
> interpretation would be
> 
> RDFNode (Jena) = node
> Literal = literal
> Blank node = blank node
> URI Resource = IRI (http://www.w3.org/TR/rdf11-concepts/#section-IRIs)
> Resource = DON'T USE FOR NODES
> 
> Is there an established term for "IRI or blank node"?
> 
> According to this, I believe the wiki pages are full of incorrect
> (imprecise) usages of the term Resource, and we can gradually fix
> that, but it's more important for everyone to be aware that for
> official specs we need to avoid the term "resource" unless we talk
> about the abstract concept in the world.
> 
> (Peter please correct me if I am wrong on my summary).
> 
> What puzzles me though is why is the root class in the RDFS
> meta-model called rdfs:Resource and not rdfs:Node?
> 
> I also notice that there are borderline usages of the term
> "resource" even in the SPARQL spec, e.g.
> 
> http://www.w3.org/TR/sparql11-query/#propertypaths
> 
> "Property paths allow for more concise expressions for some SPARQL
> basic graph patterns and they also add the ability to match
> connectivity of two resources by an arbitrary length path."
> 
> where they should have used "of two nodes" IMHO plus dozens of other
> usages of "resource" in the same document. For example this usage
> clearly contradicts the official definition that excludes "blank
> nodes":
> 
> "For a vocabulary such as FOAF, where the resources are typically
> blank nodes"
> 
> The temptation to use "resource" will certainly remain strong, and
> it's easy to get this wrong.
> 
> Holger
> 
> 
> On 12/17/2014 2:40, Peter F. Patel-Schneider wrote:
> >In RDF, a resource is an entity in the world (or maybe not in the
> >world).  RDF resources can be much more than nodes in an RDF
> >graph. Saying that an RDF resource satisfies a
> >shape/constraint/description is very different from saying that a
> >node in an RDF graph satisfies a shape/constraint/description. If
> >we are talking about resources, we might say that Dick Cheney
> >matches the shape/constraint/description unrepentant.  If we are
> >talking  about nodes, we might say that the node ex:dc in
> >
> >  ex:dc ex:bar 1 .
> >
> >matches the shape/constraint/description exactly one ex:bar and
> >all ex:bar integer.
> >
> >
> >As this is the *RDF* data shapes working group, I would object if
> >we did not use RDF terminology in the correct way.  This means
> >that I would object if any document from the working group used
> >resource in other than its RDF meaning.
> >
> >
> >Peter F. Patel-Schneider
> >Nuance Communications
> >
> 

-- 
-ericP

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Received on Thursday, 18 December 2014 00:26:50 UTC