IRIs vs. URIs in SPARQL spec

The SPARQL specs says in two places that "IRIs are a subset of RDF URI 
References that omits spaces." I have trouble seeing it as a subset for 
two reasons:

1. The  http://www.ietf.org/rfc/rfc3987.txt document that it references 
says that it "defines a new protocol element called Internationalized 
Resource Identifier (IRI) by extending the syntax of URIs to a much 
wider repertoire of characters."

2. The same document says the following:

   Systems accepting IRIs MAY also deal with the printable
   characters in US-ASCII that are not allowed in URIs,
   namely "<", ">", '"', space...

It sounds to me like URIs and not IRIs disallow spaces, and for that 
reason (as well as the fact that, in line with point 1 above, 
http://example.org/rosé counts as an IRI but not a URI) that IRIs are a 
superset of URIs, and not a subset.

Am I misunderstanding something here in what the SPARQL spec says about 
IRIs?

thanks,

Bob DuCharme

Received on Sunday, 6 March 2011 22:43:55 UTC