Voice exchange A technique of prolongation in which tones in a given arrangement of voices are later replicated in a different arrangement (inversion). Typically, a third is inverted to become a sixth in the outer parts.
In the example, taken from Variation 11, the augmented fourth and its resolution to a sixth in m. 5 are replicated as a diminished fifth resolving to a third in m. 7. This repetition provides for the Urlinie notes in the obligatory register. It is important to note that the inverted repetition does not necessarily imply a repetition of structural importance. Schenker show by the graph that both dissonance and resolution groups stand for a single
V-I progression supporting the upper voice 4-3.