RE: A summary of the proposal for resolving the issues with rdf:text --> Could you please check it one more time?



> -----Original Message-----
> From: Boris Motik [mailto:boris.motik@comlab.ox.ac.uk]
> Sent: 20 May 2009 14:39
> To: 'Alan Ruttenberg'
> Cc: 'Eric Prud'hommeaux'; Seaborne, Andy; public-rdf-text@w3.org;
> 'Sandro Hawke'; 'Axel Polleres'
> Subject: RE: A summary of the proposal for resolving the issues with
> rdf:text --> Could you please check it one more time?
> 
> Hello,
> 
> This is a purely SPARQL problem: SPARQL should specify precisely what
> the
> semantics of BGPs under the D-entailment regime is.
> 
> 
> I am just going to briefly speculate as to how this might be done. I
> strongly
> believe this should be done declaratively -- that is, without taking
> into
> account implementations. Hence, one might use the following definition:
> 
>     Given an RDF graph G and a BBP Q, a substitution s for variables in
> Q is
>     an answer to G and Q iff G D-entails s(Q).
> 
> Take the following example:
> 
> G = { <a, b, "01"^^xsd:integer> }
> Q = { <a, b, ?x> }
> 
> Then, the following substitutions are answers to Q over G:
> 
> s1 = { ?x --> "1"^^xsd:integer }
> s2 = { ?x --> "01"^^xsd:integer }
> s3 = { ?x --> "1"^^xsd:decimal }
> s4 = { ?x --> "001.000"^^xsd:decimal }
> etc.

The first SPARQL WG included a mechanism for other entailment regimes.  This framework allows any group to define their own entailment regime without requiring some future SPARQL-WG exists or be running at the time.  The framework has an approach for this situation. 

 Andy

Received on Thursday, 21 May 2009 09:20:39 UTC