Types of @xref and OpenMath's @href

Dear MathML 3 and OpenMath 3 authors,

  sorry for cross-posting, but parallel markup naturally touches both
projects.  Some of the examples for parallel markup via cross-references in
the MathML spec (http://www.w3.org/TR/MathML3/chapter5.html#mixing.cr) use
Content MathML, others use OpenMath.  The @xref attribute in MathML seems to
be of type IDREF.  The @href attribute of OpenMath is written in the same
style (e.g. href="E.1.2"), but according to the OpenMath spec, its type is not
IDREF, but xsd:anyURI.  For references to fragments, this means that they have
to be written as href="#E.1.2".  (Actually, OpenMath only specifies an
OMR/@href attribute, but no @href attribute for any other element.  So it
seems that the OpenMath schema and spec have to be extended.)

Cheers,

Christoph

-- 
Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype duke4701