Re: exercise tag issue

If it must be within the DocBook framework, maybe you can use QandAset
tag as an exercise tag with a Role attribute indicating it is an
excercise (in case you want to apply a special transformation procedure
for that element).

And there is of course an option to define your own DTD (sometimes this
is easier & simpler solution) with a unique namespace.
-- 
Yoshihiro Toda
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