Playing with patterns: Isorhythmic strategies in Gyorgy Ligeti's late piano works

This dissertation addresses two paradoxes in music that is saturated with rhythmic repetition: how it can remain interesting in the short term, and how it can convey form in the longer term. I look at the virtuosic piano etudes, piano concerto, and horn trio of twentieth-century composer Gyorgy Ligeti, which were published between 1985 and 2001. Each is in large part, if not entirely, composed of at least two repeating patterns of different duration that coincide in different ways. Some pieces return to their initial contrapuntal relationship, while others do not. I discuss specific features of their rhythmic patterns and their rhythmic-contrapuntal combination and show that despite the almost overwhelming use of repetition in these pieces, the patterns sound different each time, whether because of changes in their immediate context, or changes to the patterns themselves.;Despite these broad similarities, each piece approaches repetition in slightly different ways. Some focus on exact repetition, while other incorporate frequent adjustments, or use repeating patterns only in certain sections. My analytical chapters, Chapters 3 through 6, highlight these differences, each demonstrating a unique aspect of rhythmic counterpoint using a single etude. Chapter 7 addresses extensions to Ligeti's use of repetition, drawing on shorter excerpts from the etudes and piano concerto. It also compares rhythmic repetition to some of Ligeti's other compositional practices, including tempo fugue and microcanon. Preceding these chapters are a short and general introduction in Chapter 1, and a survey of analytical approaches to Ligeti's middle- and late-period works in Chapter 2. The latter chapter also presents more formally the theoretical foundation for the analysis of rhythmic counterpoint.