WWs, and then <a 
href="http://www.w3.org/TR/1999/REC-xml-names-19990114/">XML namespace</a> 
supports the uniqueness of QName with a local part, which is unique in a name 
space. In SWCLOS, a local part of QName corresponds to symbol name in a package, 
and a namespace for a prefix part corresponds to a lisp package. To realize such 
mapping, we need the connection between a prefix part in URI and a lisp package, 
and when URI-to-symbol mapping is irregular such as demonstrated above, we 
further need the 