- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Wed, 22 Mar 2006 09:48:12 -0500 (EST)
- To: franconi@inf.unibz.it
- Cc: eric@w3.org, connolly@w3.org, public-rdf-dawg-comments@w3.org
From: Enrico Franconi <franconi@inf.unibz.it> Subject: Re: [OK] Re: [OK?] Re: comments on "SPARQL Query Language for RDF" Date: Tue, 7 Mar 2006 19:35:27 +0100 > > On 7 Mar 2006, at 17:12, Peter F. Patel-Schneider wrote: > >> Ah. Well, for (this version of) SPARQL the scoping set contains > >> exactly the > >> URIs, the Literals, and the bnodes from the scoping graph. It is a > >> theorem that > > > > I don't see any such theorem in the documents. > > > >> under these restrictions the definitions given in 2.5 uniquely > >> identify the answer > >> set - modulo renaming of bnodes - such that the answer set is > >> exactly the > >> outcome of the homomorphisms between the query and the scoping graph. > > From section 2.5.2: > > "A pattern solution can then be defined as follows: to match a basic > graph pattern under simple entailment, it is possible to proceed by > finding a mapping from blank nodes and variables in the basic graph > pattern to terms in the graph being matched; a pattern solution is > then a mapping restricted to just the variables, possibly with blank > nodes renamed. Moreover, a uniqueness property guarantees the > interoperability between SPARQL systems: given a graph and a basic > graph pattern, the set of all the pattern solutions is unique up to > blank node renaming." > > cheers > --e. This is a claim, not a theorem (with proof). peter
Received on Wednesday, 22 March 2006 14:48:39 UTC