On 3/21/13 10:57 AM, Michel Dumontier wrote:
Kingsley,I think you raise good points. I also nominally speak of entities, their attributes and the relations that hold between them. But I think your diagram is somewhat misleading. URIs do denote (can stand in the place of) entities of interest in order to refer to and/or describe them. If you separate the identifier from what it intends to identify, then you'll need another identifier for the object of interest (and recurse). Hence, a information containing object (document, graph, file, etc) may refer to our entity of interest by some label. the document could refer to it in some statement, or may contain elaborate descriptions about it. But in no way does a document directly refer to a real world object (in does so indirectly through some token - an english name, identifier or uri, etc).m.
I don't see how my illustration conveys anything contrary to what you've just outlined. The parts:
1. An entity (in this case a Person) -- a real-world or non Web realm entity
2. An identifier that denotes the Person -- e.g., a URI3. A document that describes the person -- e.g. a Document comprised of RDF model based content in the form of an description graph (you can have many of these, each denoted with its own URI-URL based identifier).
Note: URI-URL is how I convey the fact that you can denote a Web Document using its URL. Thus, Turtle, RDF/XML, RDFa+(X)HTML etc.. documents (each with their own URI-URLs) can each be comprised of graphs describing the same entity.
Kingsley
On Thu, Mar 21, 2013 at 10:27 AM, Kingsley Idehen <kide...@openlinksw.com <mailto:kide...@openlinksw.com>> wrote:On 3/20/13 10:58 PM, David Booth wrote:Thus, to be very clear, under the existing RDF Semantics specification, a given URI does **not** necessarily map to onlyone resource.True, but I don't think the statement above always provides the clarity intended. "Resource" is a synonym of "Entity" as *now* clearly stated in the latest RDF concepts guide [1]. Once we get over the conflation inherent in "Resource" and look towards "Entity" the issue starts to get much clearer, as exemplified by RDF based Linked Data [2] and its specific use of URIs to denote "Entities" while also identifying their "Descriptor Documents". All "Resources" aren't of the same medium. The Web, Internet are mediums distinct from the medium we *refer to* as the real-world. Thus, the claim that everything is a "Resource" without medium specificity is one of the ultimate recipes for unproductive debate and confusion, as a zillion mail threads over the years have demonstrated. In the context of RDF, a URI denotes an Entity. In the context of RDF based Linked Data, a URI denotes an Entity in a manner that enables it resolve to a Web Document (denoted by its own URI which is usually a URL) that describes the denoted entity (aka. URI referent) . Links: 1. http://www.w3.org/TR/rdf11-concepts/#resources-and-statements -- showcasing the critical "Resource" fix 2. http://twitpic.com/cbk8ul -- illustrating HTTP URI duality and the Semiotic triangle .--Regards, Kingsley Idehen Founder & CEO OpenLink Software Company Web:http://www.openlinksw.com Personal Weblog:http://www.openlinksw.com/blog/~kidehen <http://www.openlinksw.com/blog/%7Ekidehen> Twitter/Identi.ca handle: @kidehen Google+ Profile:https://plus.google.com/112399767740508618350/about LinkedIn Profile:http://www.linkedin.com/in/kidehen -- Michel Dumontier Associate Professor of Bioinformatics, Carleton UniversityChair, W3C Semantic Web for Health Care and the Life Sciences Interest Grouphttp://dumontierlab.com
-- Regards, Kingsley Idehen Founder & CEO OpenLink Software Company Web: http://www.openlinksw.com Personal Weblog: http://www.openlinksw.com/blog/~kidehen Twitter/Identi.ca handle: @kidehen Google+ Profile: https://plus.google.com/112399767740508618350/about LinkedIn Profile: http://www.linkedin.com/in/kidehen
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