[5][6] Fred Lerdahl describes thematic relations as "associational" and thus outside his cognitive-based generative theory's scope of analysis.
[8] In the exposition of a fugue, the principal theme (usually called the subject) is announced successively in each voice – sometimes in a transposed form.
Examples include the pre-twelve-tone or early atonal works of Arnold Schoenberg, Anton Webern, Alban Berg, and Alois Hába.
Schoenberg once said that, "intoxicated by the enthusiasm of having freed music from the shackles of tonality, I had thought to find further liberty of expression.
Examples in the works of later composers include Polyphonie X and Structures I by Pierre Boulez, Sonata for Two Pianos by Karel Goeyvaerts, and Punkte by Karlheinz Stockhausen.