application/sparql-results+xml and namespaces

Hi all,

I encounter an interoperability problem related to the SPARQL Query Result
XML format [1], and I can't decide on which side the bug is, so I'm asking
that list...

Section 2.1 of the recommendation [2] states that:

    The SPARQL Results Document begins with sparql document element in the
    http://www.w3.org/2005/sparql-results# namespace, written as follows:

      <?xml version="1.0"?>
        <sparql xmlns="http://www.w3.org/2005/sparql-results#">
         ...
        </sparql>

Because "written as follows" seems to insist on *that* particular syntax,
it is not clear to me whether the following would be compliant:

      <?xml version="1.0"?>
        <sparql:sparql xmlns:sparql="http://www.w3.org/2005/sparql-results#
">
         ...
        </sparq:sparql>

I would expect that its (or I don't see the point of mentioning an XML
namespace in the first place), and this expectation seems to be shared
RDFLib [3] developers, because they produce the second version of the XML.

However, Corese [4] developers seems to interpret it more strictly, as it
only recognizes the first version, and not the second one (when processing
federated queries).

In any case, I'll report this problem to both, according to Postel's law
[5], but I'm curious about how other interpret this problem, and the
general consensus if there is one...


[1] http://www.w3.org/TR/rdf-sparql-XMLres/
[2] http://www.w3.org/TR/rdf-sparql-XMLres/#docElement
[3] https://github.com/RDFLib/rdflib
[4] http://wimmics.inria.fr/corese
[5] https://en.wikipedia.org/wiki/Robustness_principle