RE: [xml-dev] ID/IDREF makes XML generation NP-hard

["Bullard, Claude L (Len)" <clbullar@ingr.com>]

That's neat, Henry, and I don't mean to be mean-spirited, 
but is this a "so, but so what?" kind of thing to know? 

len

-----Original Message-----
From: ht@cogsci.ed.ac.uk [mailto:ht@cogsci.ed.ac.uk]

Somewhat surprisingly, it turns out that answering the question, for an
arbitrary XML DTD, "Are there any valid instances of the document type
defined by this DTD?", is an NP-hard problem.