> For that I'd probably say "uniquely-valued nodes" or, since I don't
> much like the word "unique" (mainly since it's so commonly abused
> these days to mean "special"), then "distinctly-valued nodes" or
> (when talking in the context, for example, of Muenchian grouping)
> "representative nodes".

However, one shouldn't hyphenate adverbs, so these terms should be "uniquely
valued nodes" or "distinctly valued nodes".

Yes, I know it's a nitpick, but, since it may end up in various printed
articles, let's get it right and make a better impression.