- From: Patrick Stickler <patrick.stickler@nokia.com>
- Date: Wed, 13 Feb 2002 13:28:07 +0200
- To: Pat Hayes <phayes@ai.uwf.edu>, Brian McBride <brian_mcbride@hp.com>
I would like to make the following proposal, first just now to you Pat (and Brian), and if you are cool with it, then to the broader DT subgroup. 1. We keep all three idioms. 2. We include the following manditory/implied/automatic statements in the DT spec: rdfs:Datatype rdf:type rdfs:Class . rdf:dtype rdfs:subPropertyOf rdf:type . rdf:dtype rdfs:range rdfs:Datatype . rdfs:drange rdfs:subPropertyOf rdfs:range . rdfs:drange rdfs:range rdfs:Datatype . (if you don't like 'drange', feel free to suggest some other name, though actually, I think we can have alot of fun with it ;-) These give us a completely local idiom that applications can recognize without additional RDFS statements in the graph, based on the above fixed knowledge. It also allows lexical datatypes to be used to constrain only value spaces without recourse to defining non-lexical types just for that purpose. Thus rdfs:range entails rdf:type and rdfs:drange entails rdf:dtype. This also keeps the present semantics of rdf:type and rdfs:range untouched by the DT solution. 3. The definition of 'local' is corrected to reflect the meaning set forth in the desiderada, meaning not requiring any statements outside the idiom triples for recognition and interpretation (all automatic statements/closure rules in the MT though still apply) 4. It is clearly pointed out that the datatype triple idiom is not a proper local idiom, per the definition above, and requires the explicit statements ddd rdf:type rdfs:Datatype . ddd rdfs:subPropertyOf rdf:value . in order for an application to "know" that it is a datatyping idiom without special knowledge of the datatype itself (I don't accept any application specific knowledge as valid in this case, only knowledge in the RDF graph or mandated by the RDF DT spec) 5. It is stated clearly that the doublet idiom is the only fully local idiom, and users who need or wish to use a fully local idiom should use the doublet idiom. 6. That it is clearly pointed out that coreference/merging using the datatype triple idiom is not a feature of RDF datatyping (even if the datatype triple idiom facilitates this) but is application-specific and that no user should automatically presume that any arbitrary graph using the datatype triple idiom has fully merged coreferent bNodes -- though a given application providing access to a given graph, or the producer/publisher/owner of a single specific graph in isolation is free to make such claims. The last three items serve as "guard rails" for users so that they understand the nature/utility/limitations of the different idioms and what to expect (and not expect) from each. With the above changes, then I am happy to recommend the convergence proposal, with all three idioms, both to the WG and to the RDF community at large. What do you say? Patrick -- Patrick Stickler Phone: +358 50 483 9453 Senior Research Scientist Fax: +358 7180 35409 Nokia Research Center Email: patrick.stickler@nokia.com
Received on Wednesday, 13 February 2002 06:26:59 UTC