Based on review on the mailing list and at last Core WG call, I consider this to be closed with no changes. Just summarizing with the following observation:
1. We are not using anything that is really being scoped out of the new work by W3C RDF WG, for example we only use rdf:* class/predicates and blank nodes. 2. There really isn't an acceptable alternative. Alternatives require us to reach a similar conclusion to what is defined using reification. I will continue to track RDF WG activity with reification with this usage in mind. Thanks, Steve Speicher | IBM Rational Software | (919) 254-0645 > From: Steve K Speicher/Raleigh/IBM@IBMUS > To: [email protected], > Date: 06/12/2012 03:11 PM > Subject: [oslc-core] Rethinking link labels without reified statements > Sent by: [email protected] > > In looking at what is on the roadmap for the W3C RDF Working Group in > considering deprecating reified statements [1] I took the action to > explore the way we currently do things like "link labels" [2] using the > recommended alternative of named graphs[3]. I'm sending this note out to > see if anyone else has any interesting insight on how this can be > accomplished. I plan to send a note to the RDF WG as well. > > To be honest, I struggle to find a clean way to do this with named graphs. > Added to some of the challenges is how to define a simple PATCH format > that can be used to patch these reified statements. > > Take for example this simple change request: > @prefix ex: <http://example.com/bugtracker> . > @prefix oslc: <http://open-services.net/ns/core#> . > @prefix oslc_cm: <http://open-services.net/ns/cm#> . > @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . > @prefix dcterms: <http://purl.org/dc/terms/> . > > <http://example.com/bugs/2314> > a oslc_cm:ChangeRequest ; > oslc_cm:relatedChangeRequest <http://myserver/mycmapp/bugs/1235> , > <http://remoteserver/mycmapp/defects/abc123> . > > _:b1 > a rdf:Statement; > rdf:subject <http://example.com/bugs/2314>; > rdf:predicate oslc_cm:relatedChangeRequest; > rdf:object <http://myserver/mycmapp/bugs/1235>; > dcterms:title "My special link title". > > So if I want to NOT use reified statements I'd have to model this > relationship a bit differently. One idea would be to use a named graph > for the link statements. > The questions that need to be answered with this approach are: > > 1. Simply how to form that graph and/or how to relate the graph with the > right "relationship" triple? > > In thinking through this, it feels like I'm inventing reification and > doesn't seem like the desired outcome. Let's try to force it for a moment > and say we can "compute" the graph name based on the relationship triple. > So for my example above, we have something horrible like (not encoding): > Graph name = < http://example.com/bugs/2314|http://open-services.net/ns/cm# > relatedChangeRequest|http://myserver/mycmapp/bugs/1235> > > 2. What is the subject of the triples within this new named graph? > The subject and object of the relationship triple don't appear to be the > right choice. Though, since we have this special private graph, perhaps > we can just use the object to pick one since we shouldn't have any > conflicts. > > So the example becomes: > > @prefix ex: <http://example.com/bugtracker> . > @prefix oslc: <http://open-services.net/ns/core#> . > @prefix oslc_cm: <http://open-services.net/ns/cm#> . > @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> . > @prefix dcterms: <http://purl.org/dc/terms/> . > > <http://example.com/bugs/2314> > a oslc_cm:ChangeRequest ; > oslc_cm:relatedChangeRequest <http://myserver/mycmapp/bugs/1235> , > <http://remoteserver/mycmapp/defects/abc123> . > > :<http://example.com/bugs/2314|http://open-services.net/ns/cm# > relatedChangeRequest|http://myserver/mycmapp/bugs/1235> = { > <http://myserver/mycmapp/bugs/1235> dcterms:title "My special link > title". # This is a lie, not right subject > } > > This seems like a complete non-obvious abuse of this. Hopefully someone > sees a more clear way to leverage named graphs and why I'm taking this > discussion to the mailing list. If not, we can provide this feedback to > RDF WG and see if they have a proper solution or will justify keeping > reification or some subset. > > [1] - http://www.w3.org/2011/rdf-wg/track/issues/25 , > http://open-services.net/pipermail/oslc-core_open-services.net/2012- > February/001229.html > [2] - > http://open-services.net/bin/view/Main/OslcCoreSpecAppendixLinks#2_Anchor > [3] - > http://www.w3.org/TR/2012/WD-rdf11-concepts-20120605/#section-dataset > > Thanks, > Steve Speicher | IBM Rational Software | (919) 254-0645 > > > _______________________________________________ > Oslc-Core mailing list > [email protected] > http://open-services.net/mailman/listinfo/oslc-core_open-services.net >
