Prolongation and Its Limits: The Compositions of Wayne Shorter.

This article examines four jazz compositions by Wayne Shorter, "El Toro," "Iris," "Pinocchio," and "Face of the Deep," to determine the applicability of analysis based on harmonic prolongation, voice leading, and the derivation of structural levels to works whose tonality is ambiguous. The works, in the order listed, become progressively more ambiguous harmonically, and, accordingly, the application of such Schenker-based techniques becomes progressively less convincing. In the final piece, "Face of the Deep," the inference of harmonic prolongation becomes untenable. The author also proposes a series of style factors that can be rated from 0 to 10 to help determine the applicability of prolongational analysis to works in the jazz improvisational repertory. [ABSTRACT FROM AUTHOR]