Bob,

SPARQL will handle URIs that aren't HTTP URIs. For example, I can perform SPARQL queries on uBio RDF that has some namespaces and resources identified by LSIDs. 

By Semantic web tools I'm thinking more generally, such as data browsers and triple stores, that is, anything that reads RDF and expects to be able to follow any resource in the RDF. If those resources aren't HTTP URIs then these tools won't know how to fetch them. 

One case where SPARQL does need HTTRP URIs is the "FROM" statement, where it can fetch data from the web as part of the query. 

Rod



On 9 Jun 2007, at 14:54, Bob Morris wrote:

a. To the best of my understanding, nothing in the RDF syntax implies
that the URI scheme must be the  HTTP URI scheme, common as that is.

b. Some of your arguments here seem to depend on that (e.g. your point 3 ).

c. My conclusion from a. is that  any Semantic Web tool, e.g. a SPARQL
processor, should usually be deemed broken if it behaves differently
on an HTTP URI than it does on any other URI.

See also http://copia.ogbuji.net/blog/2007-05-26/linked-data-is-overseling-http

Bob


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