I like the idea, but isn't an arrangement a set of sequences of notes assigned to instruments / voices? Fundamentally, a "documented" sequence of notes? (where

I like the idea, but isn't an arrangement a set of sequences of notes assigned to instruments / voices? Fundamentally, a "documented" sequence of notes? (where a note has a duration, an instrument, a start time, a function defining the dynamic, a pitch (possibly a function), possibly an intent, possibly a part of the lyrics if applicable). Where to draw the line?