/ Vitaly Ostanin <vy...@vzljot.ru> was heard to say:
| I'm join modular DocBook/XML documents and get errors for already
| declared values of ID attributes (each in separated documents).
| It's possible to do common attribute "id" uniq not for all document,
| in some levels only ?
| It's possible to add <fallback> element within <xref> element ? And
| also for all idref's attributes?
Documents with duplicated IDs are not valid. If you apply a stylesheet
(or any other process) to an invalid document, all bets are off.