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.