Re: Keys and select distinct - is that the solution ?

> couldn't I say something like take all the elements whose content is
> not in any preeceding sibling content ???

you could, but that means that while checking each item you check all
previous items to see if it's the same content. For large documents
thisis very inefficient. The muenchian grouping technique speeds things
up (often by orders of magnitute) by first making a key of all the
items with a given value so you don't need to search preceding siblings
to check if the value occurs, that information is all pre-cached in the
key (which is probably a hash table of some sort).

David

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