BaseChar problem in XML 1.0?

Hello XML Editors,

Here's a question that just came up regarding the definition
of allowable identifier characters in XML.

From the XML spec,

Production [85]  BaseChar includes the characters [#x2180-#x2182]. 

These are Roman Numerals
    1000    CD
    5000    (No reasonable ASCII approximation)
   10000    (No reasonable ASCII approximation)

BaseChar does not include the remaining Unicode Roman Numerals,
which encompass the range [#x2160-#x2183]

I checked with Mark Davis, and there is nothing from a
Unicode perspective that sets the three included characters
apart from the rest of the Unicode Roman Numerals.  It would
seem that they either all ought to be allowed or disallowed as
BaseChars.

Unicode's recommendations for Identifier characters allow them
all.

Something does not seem right.  Is there some logic here
that escapes me, or is it possible that the inclusion of
these characters is an editing error, or ???

 

  -- Andy Heninger,      IBM Cupertino, XML Technology Group
      heninger@us.ibm.com