Interval cycles, "unfold [i.e., repeat] a single recurrent interval in a series that closes with a return to the initial pitch class", and are notated by George Perle using the letter "C", for cycle, with an interval-class integer to distinguish the interval. Thus the diminished-seventh chord would be C3 and the augmented triad would be C4. A superscript may be added to distinguish between transpositions, using 0–11 to indicate the lowest pitch class in the cycle.Perle, George (1990). The Listening Composer, p. 21. California: University of California Press. .
interval cycles "unfold [ie repeat] a single recurrent interval in a series that closes with a return to the initial pitch class" and are notated by george perle using the letter "c" for cycle with an interval-class integer to distinguish the interval thus the diminished-seventh chord would be c3 and the augmented triad would be c4 a superscript may be added to distinguish between transpositions using 0–11 to indicate the lowest pitch class in the cycleperle george (1990) the listening composer p 21 california university of california press 