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Re: Input needed from RDF group on JSON-LD skolemization

From: Ivan Herman <ivan@w3.org>
Date: Fri, 14 Jun 2013 08:54:16 +0200
Message-ID: <51BABE18.1080101@w3.org>
To: David Booth <david@dbooth.org>
CC: public-rdf-comments <public-rdf-comments@w3.org>
David,

I understand why the current 'genid' does not work for a 100%. But I am a bit
uneasy to tie this to json-ld. There may be, in future, other syntaxes that have
this feature, do we want to bind them to json-ld, too? Something like
general-genid (referring to the unofficial term of generalized RDF) or something
like that. I realize we can loose lots of time finding the right term, but I
think it is worth coining something that is syntax neutral. (We can even do
something like gen-genid:-)

Ivan


David Booth wrote:
> The JSON-LD group would like input from the rest of the RDF Working Group about
> skolemization.
> 
> During the last JSON-LD call
> http://json-ld.org/minutes/2013-06-11/
> there was discussion of a proposal to require skolemization of JSON-LD blank
> nodes, when interpreting JSON-LD as RDF, in cases where they otherwise would be
> converted to RDF blank nodes but are used where a blank node is not allowed in
> RDF.  (At present they are prohibited as predicates and as graph names.)
> 
> The proposal was #1 at:
> http://lists.w3.org/Archives/Public/public-rdf-comments/2013Jun/0072.html
> [[
> 1. In RDF conversion algorithms in JSON-LD 1.0 Processing Algorithms and
> API,
> http://json-ld.org/spec/latest/json-ld-api/#rdf-conversion-algorithms
> specify that **when JSON-LD is interpreted as RDF,** (i.e., when the
> JSON-LD model is converted to the RDF model) skolem IRIs MUST be
> generated using the well-known URI suffix "json-ld-genid" for any
> JSON-LD blank node that would otherwise be mapped to an RDF blank node
> in a position where an RDF blank node is not permitted.  Conversely,
> when RDF is serialized as JSON-LD (or when an RDF model is converted to
> a JSON-LD model), skolem IRIs having the well-known URI suffix
> "json-ld-genid" SHOULD be serialized as JSON-LD blank nodes.  Finally,
> register the well-known URI suffix "json-ld-genid", in accordance with
> RFC5785:
> http://tools.ietf.org/html/rfc5785
> BACKGROUND NOTE: The existing well-known URI suffix "genid" is for
> converting to/from RDF blank nodes (in positions where blank nodes are
> *permitted* in RDF), whereas "json-ld-genid" will be used for *avoiding*
> blank nodes (in positions where they are not allowed in RDF).
> ]]
> 
> There was also some follow up email discussion about what  well-known URI suffix
> to use, but that is probably a minor issue.
> 
> Before making a decision about this proposal, the JSON-LD group would like to
> know whether others think this proposal is reasonable and viable.  The goal is
> to make JSON-LD function more predictably as a concrete RDF syntax.  At present,
> such skolemization is optional, which means that a user cannot be assured of
> obtaining legal RDF or knowing whether the otherwise-illegal triples will simply
> be dropped.
> 
> Please let us know your thoughts.
> 
> Thanks,
> David
> 
> 

-- 
Ivan Herman, W3C
Home: http://www.w3.org/People/Ivan/
mobile: +31-641044153
http://www.ivan-herman.net/foaf#me

Received on Friday, 14 June 2013 06:54:44 UTC

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