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Re: Skolemization and RDF Semantics

From: Steve Harris <steve.harris@garlik.com>
Date: Wed, 27 Apr 2011 22:01:43 +0100
Cc: Ivan Herman <ivan@w3.org>, "RDF-WG public-rdf-wg@w3.org" <public-rdf-wg@w3.org>
Message-Id: <74013DEC-7F02-446E-BB9F-FE896D50AB34@garlik.com>
To: Richard Cyganiak <richard@cyganiak.de>
On 2011-04-27, at 17:51, Richard Cyganiak wrote:
> On 27 Apr 2011, at 17:28, Ivan Herman wrote:
>> | (Some intro text explaining what a skolem URI is)
>> |
>> | Systems wishing to skolemise bNodes, and expose those skolem
>> | constants to external systems (e.g. in query results) SHOULD
>> | mint a "fresh" (globally unique) URI for each bNode. Systems
>> | performing skolemisation may wish to do so in a way that they
>> | can recognise the constants once skolemised, and map back to
>> | the source blank nodes where possible.
>> |
>> | Systems which want their skolem constants to be identifiable
>> | by other systems SHOULD use the .well-known URI prefix. (W3C
>> | will register an appropriate .well-known URI prefix with IANA
>> | as per RFC 5758. Details TBD.)
>> - do we stick to .well-known/genid, or do we want to use other terms instead of genid (there were some discussion about that)
> Personally I'm a fan of .well-known/skolem :-) Obscure, but once you know what they are, you'll recognize them. genid is too boring. bnode confuses some people.

I think "skolem" is a pretty obscure piece of jargon.

>> - do we want to also have a non-http versions of the URI-s that are likely to be more readable. The tag: scheme came up (though that is not necessarily more readable) or the urn:genid: version. 
> Personally I'm -0 on that. The phrasing above leaves open the possibility of using any other type of URI, including tag: or urn:uuid:.
> We should maybe add something like, “Systems MAY make the .well-known URIs resolvable.” This would make clear that, despite being http: URIs, they may or may not resolve.

I think a urn: or similar scheme would be useful.

>> Tracker, this is relevant for ISSUE-40
> Thanks! Somehow there seems to be a duplicate of that issue now, with number 41?

- Steve

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Received on Wednesday, 27 April 2011 21:02:14 UTC

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