Complex sentence: His works are cited as notable examples of post-war experimental and contemporary music, and were tied to New York's downtown music and Fluxus art scenes, often calling into question the nature and definition of music.
Split into simpler sentences: His works are cited as notable examples of post-war experimental and contemporary music, and were tied to New York's downtown music and Fluxus art scenes. Young's work often calls into question the nature and definition of music.