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Re: Proposal for ISSUE-40 Skolemization

From: Steve Harris <steve.harris@garlik.com>
Date: Thu, 12 May 2011 15:14:55 +0100
Cc: Richard Cyganiak <richard@cyganiak.de>, "RDF-WG public-rdf-wg@w3.org" <public-rdf-wg@w3.org>
Message-Id: <0E69464F-10F1-435E-819E-B9BBBCCC9674@garlik.com>
To: Ivan Herman <ivan@w3.org>
Hmmm... I'm hard enough to google for as it is!

- Steve

On 2011-05-12, at 13:12, Ivan Herman wrote:

> Just to clarify: in the course of the discussion we mentioned the alternative of shorter and friendlier, albeit non dereferencable URIs (not replacing the .well-known but as another possibility); I think one idea was to use urn:steveH:XXXXX. Is the intention that we do not go down that line? Just checking...
> 
> Ivan
> 
> P.S. I actually think steveH is a perfect keyword:-)
> 
> 
> 
> On May 12, 2011, at 13:47 , Richard Cyganiak wrote:
> 
>> Below is a complete proposal including intro text and detailed wording about the .well-known mechanism, based on a combination of the original proposal from the wiki, and PatH's comments. It's also on the wiki here:
>> http://www.w3.org/2011/rdf-wg/wiki/Skolemisation#Updated_Proposal
>> 
>> 
>> On 28 Apr 2011, at 06:10, Pat Hayes wrote:
>>> I would prefer to avoid the "skolem" terminology altogether.
>> 
>> I am fine with avoiding “skolem”. But I believe that *some* term is necessary. First, writing the spec is awkward if one has to repeatedly refer to “an IRI that has been introduced solely to replace a blank node”. Second, I believe that eventually we and others will come to use *some* shorthand term in everyday technical conversation, so why not just bite the bullet and define a term for it in the spec.
>> 
>> I'll stick to “Skolem IRI” for now, until another term has been proposed. I removed mentions of “Skolemization”.
>> 
>>> it really ought to be capitalized, as it is a direct use of the name of Theo Skolem.
>> 
>> Thoralf. I have now capitalized the term.
>> 
>>> It is not clear what is meant by " identifiable by other systems". Identifiable as being skolem URIs? Or in some stronger sense of 'identifiable'? If the former, I suggest the wording "identifiable by other systems as Skolem URIs"
>> 
>> This wording seems fine. I ended up using “recognizable outside of the system boundaries” to avoid “identify” and talking about “systems and other systems”.
>> 
>> The complete proposal is below.
>> 
>> Best,
>> Richard
>> 
>> 
>> PROPOSAL FOR ADDRESSING ISSUE-40
>> 
>> Add the following in RDF Concepts, Section 6.6 Blank Nodes
>> http://www.w3.org/TR/rdf-concepts/#section-blank-nodes
>> 
>> 
>> 6.6.1 Replacing blank nodes with IRIs
>> 
>> Blank nodes do not have an intrinsic name in the RDF abstract syntax. In situations where such a name is required, implementations MAY systematically replace blank nodes in an RDF graph with IRIs. Systems wishing to do this SHOULD mint a new, globally unique IRI for each blank node. Such IRIs are known as ''Skolem IRIs''.
>> 
>> Systems may wish to mint Skolem IRIs in such a way that they can recognize the IRIs as having been introduced solely to replace a blank node, and map back to the source blank node where possible.
>> 
>> Systems which want Skolem IRIs to be recognizable outside of the system boundaries SHOULD use a well-known IRI [RFC5785] with the registered name “SteveH”. This is an IRI that uses the HTTP or HTTPS scheme, or another scheme that has been specified to use well-known IRIs; and whose path component starts with /.well-known/SteveH/ .
>> 
>> For example, the authority responsible for the domain “example.com” could mint the following recognizable Skolem IRI:
>> 
>> http://example.com/.well-known/SteveH/d26a2d0e98334696f4ad70a677abc1f6
>> 
>> Note: “SteveH” is a placeholder. Names currently under discussion are “genid”, “bnode”, “skolem”.
>> 
>> Note: RFC 5758 only specifies well-known URIs, not IRIs. For the purpose of this document, a well-known IRI is any IRI that results in a well-known URI after IRI-to-URI mapping [RFC3987].
>> 
>> 
> 
> 
> ----
> Ivan Herman, W3C Semantic Web Activity Lead
> Home: http://www.w3.org/People/Ivan/
> mobile: +31-641044153
> PGP Key: http://www.ivan-herman.net/pgpkey.html
> FOAF: http://www.ivan-herman.net/foaf.rdf
> 
> 
> 
> 
> 
> 

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Received on Thursday, 12 May 2011 14:15:34 GMT

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